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Final Technical Report 2007 Surface Water Ambient Monitoring Program (SWAMP) Report on the Tijuana Hydrologic Unit January 2008

SURFACE WATER AMBIENT MONITORING PROGRAM (SWAMP) REPORT ON THE TIJUANA HYDROLOGIC UNIT

Raphael D. Mazor Ken Schiff

Southern California Coastal Water Research Project 3535 Harbor Blvd., Suite 110

Costa Mesa, CA 92626 www.sccwrp.org

Prepared for the California Regional Water Quality Control Board, San Diego Region (Region 9).

This project was funded by the Surface Water Ambient Monitoring Program.

Technical Report 527_Tijuana

http://www.sccwrp.org/

SWAMP Report on the Tijuana Hydrologic Unit

TABLE OF CONTENTS

1. Abstract .........................................................................................................1 2. Introduction ...................................................................................................2

2.1 Geographic Setting..................................................................................3 2.1.1 Climate..................................................................................................3 2.1.2 Hydrology..............................................................................................6 2.1.3 Land Use within the Watershed ............................................................6 2.1.4 Beneficial Uses and Known Impairments in the Watershed..................8

3. Methods ........................................................................................................8 3.1 Indicators ...............................................................................................10 3.1.1 Water chemistry..................................................................................10 3.1.2 Toxicity................................................................................................11 3.1.3 Tissue .................................................................................................11 3.1.4 Bioassessment ...................................................................................11 3.1.5 Physical Habitat ..................................................................................11 3.2 Data Analysis.........................................................................................12 3.2.1 Thresholds ..........................................................................................12 3.2.2 Quality Assurance and Quality Control (QA/QC) ................................16

4. Results ........................................................................................................17 4.1 Water Chemistry....................................................................................17 4.2 Toxicity ..................................................................................................28 4.3 Tissue....................................................................................................29 4.4 Bioassessment ......................................................................................30 4.5 Physical Habitat.....................................................................................34

5. Discussion...................................................................................................36 6. Literature Cited............................................................................................41 7. Appendices .................................................................................................44

APPENDIX I ..............................................................................................I - 1 APPENDIX II ............................................................................................II - 1 APPENDIX III ..........................................................................................III - 1 APPENDIX IV......................................................................................... IV - 1

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LIST OF FIGURES

Figure 1. Location of the Tijuana HU................................................................3 Figure 2. Rainfall and sampling events at three stations in the San Diego

region .........................................................................................................5 Figure 3. The Tijuana HU, including major waterways. ....................................6 Figure 4. Land use within the Tijuana watershed .............................................7 Figure 5. Location SWAMP and non-SWAMP sampling locations .................10 Figure 6. Aquatic life threshold exceedances for water chemistry at SWAMP

sites..........................................................................................................27 Figure 7. Human health threshold exceedances for water chemistry at

SWAMP sites ...........................................................................................28 Figure 8. Frequency of toxicity at SWAMP sites ............................................29 Figure 9. IBI scores at sites in the Tijuana HU ...............................................32 Figure 10. Mean IBI scores at each bioassessment site and each season ....33 Figure 11. IBI values for each year and site ...................................................34 Figure 12. Assessment of physical habitat at SWAMP sites ..........................35 Figure 13. Summary of the ecological health of SWAMP sites. .....................40

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LIST OF TABLES

Table 1. Watersheds monitored under the SWAMP program. .........................2 Table 2. Sources of data used in this report.....................................................8 Table 3. SWAMP sampling site locations.........................................................9 Table 4. Non-SWAMP sampling site locations .................................................9 Table 5. Threshold sources............................................................................13 Table 6. Water chemistry thresholds for aquatic life and human health

standards .................................................................................................14 Table 7. Number of anthropogenic organic constituents detected at each site

.................................................................................................................17 Table 8. Frequency of detection of anthropogenic organic compounds .........17 Table 9. Frequency of water chemistry threshold exceedances.....................23 Table 10. Frequency of SWAMP sites with aquatic life and human health

threshold exceedances for each constituent ............................................25 Table 11. Number of constituents exceeding thresholds at each SWAMP site.

.................................................................................................................26 Table 12. Frequency of toxicity detected for each endpoint and at each site .29 Table 13. Mean and standard deviation of IBI scores at bioassessment sites

within the Tijuana HU ...............................................................................31 Table 14. Score for each component of physical habitat................................35 Table 15. Summary of the ecological health for five SWAMP sites in Tijuana

HU............................................................................................................39

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1. ABSTRACT

In order to assess the ecological health of the Tijuana Hydrologic Unit (San Diego County, CA), water chemistry, water and sediment toxicity, benthic macroinvertebrate communities, and physical habitat were assessed at multiple sites. Water chemistry and toxicity were assessed under SWAMP between 2005 and 2006. Bioassessment samples were collected under SWAMP and other programs between 1999 and 2006. Physical habitat was assessed under SWAMP in 2007. Although impacts to human health were also assessed, the goal of this monitoring program was to examine impacts to aquatic life in the watershed. Most of these ecological indicators showed evidence of widespread impacts to the watershed, although severity was greater at sites receiving drainage from Mexico (i.e., Tijuana River mainstem and Tecate Creek). For example, all sites (n = 4) exceeded aquatic life thresholds for several water chemistry constituents, but the number and persistence of exceedances was lower at sites within the United States. Nutrients and physical constituents of water quality (e.g., pH, conductivity) were impacted at sites throughout the watershed, and anthropogenic organic constituents affected sites on streams entering from Mexico. Toxicity was evident at all sites, although severity was greater at the Tijuana River and Tecate Creek sites, where sediment samples increased mortality to Hyalella azteca. Sub-lethal toxicity to Hyalella was evident in all samples from all sites. Bioassessment samples collected at 15 sites (72 samples) ranged from very poor condition to good, with mean annual IBIs ranging from 8.6 to 70.0. Sites with high IBIs had benthic macroinvertebrate communities similar to those found in reference condition, and were clustered in the northern interior portions of the watershed, such as the upper parts of Cottonwood Creek. Physical habitat at La Posta Creek showed signs of moderate degradation, with a mean physical habitat score of 13 out of 20. Embeddedness, velocity-depth regime, and sediment deposition were the most degraded components of physical habitat. Multiple stressors, such as contaminated water and sediment, industrial and urban discharges, and alteration of physical habitat, were likely responsible for the poor health of the southern portions of the watershed. Despite limitations of this assessment (e.g., uncertain spatial and temporal variability, low levels of replication, non-probabilistic sampling, and lack of thresholds for several indicators), multiple lines of evidence support the conclusion that portions of the Tijuana watershed receiving drainage from Mexico are in poor ecological condition, and that the northern interior of the watershed is in moderate to good ecological condition.

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2. INTRODUCTION

The Tijuana hydrologic unit (HU 911) is in San Diego County. Home to over 1,000,000 people, the watershed represents an important water resource in one of the most arid regions of the nation. Despite strong interest in the surface waters of the Tijuana HU, a comprehensive assessment of the ecological health of these waters has not been conducted. The purpose of this study was to assess the health of the watershed using data collected in 2005 and 2006 under the Surface Waters Ambient Monitoring Program (SWAMP), and data collected by National Pollution Discharge Elimination System (NPDES) permittees. SWAMP monitoring efforts rotated among sets of watersheds, ensuring that each HU is monitored once every 5 years (Table 1). These programs collected data to describe water chemistry, water and sediment toxicity, physical habitat, and macroinvertebrate community structure. By examining data from multiple sources, this report provides a measure of the ecological integrity of the Tijuana HU.

Table 1. Watersheds monitored under the SWAMP program. Year (Fiscal year) Sample collection Hydrologic unit HUC1 (2000-2001) 2002 Carlsbad 904

2002 Peñasquitos 9062 (2001-2002) 2002-2003 San Juan 901

2003 Otay 9103 (2002-2003) 2003 Santa Margarita 902

2003 San Dieguito 9054 (2003-2004) 2004-2005 San Diego 907

2004-2005 San Luis Rey 9035 (2004-2005) 2005-2006 Pueblo San Diego 908

2005-2006 Sweetwater 9092005-2006 Tijuana 911

There are two objectives for this assessment: 1) To evaluate the condition

of SWAMP sites; and 2) To evaluate the overall condition of the watershed. Evaluations were based on multiple indicators of ecological integrity, including water chemistry, water and sediment toxicity, biological assessment of benthic macroinvertebrate communities, and physical habitat assessment. This report is organized into four sections. The first section (Introduction) describes the geographic setting in terms of climate, hydrology, and land use within the watershed. The second section (Methods) describes the approach to data collection, assessment indicators, and data analysis. The third section (Results) contains the results of these analyses. The fourth section (Discussion) integrates evidence of impact from multiple indicators, describes the limitations of this assessment, and summarizes the overall health of the watershed.

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Although the Tijuana River watershed includes extensive portions of Mexico (1253 mi2, or 73% of the watershed), this report focuses on the waters with the Tijuana HU, defined as the streams of the watershed within California.

2.1 Geographic Setting

The Tijuana HU is the northern portion of the Tijuana River watershed. The watershed extends from the peninsular mountain ranges, such as the Cuyamacas, to the Pacific Ocean, just south of San Diego Bay (Figure 1). The highest peak within the watershed is Cuyapaipe Peak, at 1,944 m elevation (Institute for Regional Studies of the Californias 2005)

Figure 1. San Diego region (purple) includes portions of San Diego, Riverside, and Orange counties. The Tijuana HU (tan, shaded) is located entirely within San Diego County, although most of the Tijuana River watershed is in Mexico. 2.1.1 Climate

The Tijuana HU, like the entire San Diego region, is characterized by a mediterranean climate, with hot dry summers and cool wet winters. Average monthly rainfalls measured at the Lindberg Airport (SDG) in San Diego, California between 1905 and 2006 show that nearly all rain fell between the

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months of October and April, with hardly any falling between the months of May and September (California Department of Water Resources 2007). The wettest month was January, with an average rainfall of 2.05"). Average annual rainfall at this station was 10.37". Daily rainfall measured at Mount Laguna (near the inland end of the HU), Campo (in the central part of the HU) and at Sea World (near the coast outside the HU) shows considerable variability in rainfall throughout the HU (National Oceanic and Atmospheric Administration 2007) (Figure 2).

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Figure 2. Rainfall and sampling events at stations in the San Diego region. A. Average precipitation for each month at the Lindberg Station (DWR station code SDG), based on data collected between January 1905 and November 2006. B. Location of the Sea World, Camp, and Mount Laguna gauges. C. Storm events and sampling events in the Tijuana HU. The top three plots show daily precipitation between 1998 and 2007 at the three stations. The bottom plot shows the timing of sampling events. Non-SWAMP water chemistry is shown as black circles. Non-SWAMP bioassessment is shown as black downward triangles. SWAMP bioassessment is shown as upward white triangles. Swamp water chemistry and toxicity is shown as white circles.

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2.1.2 Hydrology The Tijuana HU consists of the northern portion of the Tijuana River Watershed. Major tributaries within the United States include Pine Valley Creek, Cottonwood Creek, Wilson Creek, and La Posta Creek. Campo Creek begins in the United States but meets with Tecate Creek in Mexico. Tecate Creek is mostly within Mexico, but enters the mainstem in the United States less than a mile from the border. The mainstem crosses from the United States into Mexico, and returns north before entering the Tijuana Estuary, one of the most extensive salt marshes remaining in southern California (Institute for Regional Studies of the Californias 2005). Major waterbodies within the HU include Morena Reservoir and Barrett Lake.

Figure 3. The Tijuana watershed, including major waterways. 2.1.3 Land Use within the Watershed

The majority (73%) of the Tijuana watershed is under Mexican jurisdiction, with the cities of Tijuana and Tecate being the largest population centers. Within California, most of the HU (95%) is unincorporated portions of San Diego County.

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The cities of San Diego and Imperial Beach have jurisdiction over 4.7% and 0.7% of the HU, respectively. Caltrans is a major landowner within the HU, and has jurisdiction over all major freeways and highways. Indian reservations, including the La Posta, Campo, Cuyapaipe, and Manzanita Reservations, are found within the watershed (SANDAG 1998, Institute for Regional Studies of the Californias 2005).

Within the Tijuana HU, much of the watershed (90%) is undeveloped open space. Developed urban land accounts for 6% of the HU, and agriculture occupies 4% of the HU (SANDAG 1998). In the Mexican portion of the watershed, developed land comprises only 3%, and agriculture comprises 14% of the total area (Figure 4) (Center for Earth Systems Analysis Research 2000, Institute for Regional Studies of the Californias 2005). Within California, major protected areas include the Cleveland National Forest and Lake Morena County Park. Protected around the lower portions of the watershed include the Tijuana River National Estuarine Research Reserve, Border Field State Park, and the Tijuana River Valley Regional Park (SANDAG 1998, Institute for Regional Studies of the Californias 2005).

Figure 4. Land use within the Tijuana HU. Undeveloped open space is shown as green. Agricultural areas are shown as orange. Urban and developed lands are shown as pink, with industrial areas indicated by a darker shade.

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2.1.4 Beneficial Uses and Known Impairments in the Watershed

The Tijuana HU is designated to support many beneficial uses. Beneficial uses in the watershed include municipal; agriculture; industrial service supply; industrial processes; freshwater; recreation; warm and cold freshwater habitat; wildlife habitat; and rare, threatened, or endangered species. Some streams in the Tijuana HU have been exempted from municipal uses (Appendix I).

Two streams in the Tijuana HU are listed as impaired on the 303(d) list of

water quality limited segments, affecting a total of 8.9 stream miles. These streams include Pine Valley Creek and the Tijuana River mainstem. Known stressors include bacteria, phosphorus, turbidity, eutrophication, low dissolved oxygen, pesticides, solids, synthetic organics, trace elements, and trash (Appendix I).

3. METHODS This report combines data collected under SWAMP with data from California Department of Fish and Game (CDFG) and NPDES monitoring (Table 2). Six sites of interest were sampled under SWAMP in the Tijuana HU in 2002 (Table 3; Figure 5). Water chemistry and toxicity were measured at 4 sites. Physical habitat was assessed at one site (La Posta Creek). Bioassessment samples were collected under SWAMP at 2 additional sites. In addition, bioassessment samples were collected by the CDFG Aquatic Bioassessment Laboratory (ABL) and the County of San Diego as part of its NPDES permit (between 2002 and 2005) at 14 sites, including 3 of the sites monitored under SWAMP. In addition to bioassessment, conventional water chemistry (e.g., temperature, conductivity, dissolved oxygen) was also measured at sites sampled by San Diego County NPDES. When two non-SWAMP sites were located within 500 meters of each other, they were treated as a single site. This distance was based on published measures of spatial correlation of benthic communities in streams (Gebler 2004). Non-SWAMP samples were collected between 1999 and 2005; in some cases, non-SWAMP sites were very close to SWAMP sites (Table 4; Figure 5). Table 2. Sources of data used in this report. Program Indicators YearsSWAMP Water chemistry, bioassessment, toxicity, physical habitat 2005-2006CA Department of Fish and Game Bioassessment 1999-2005San Diego County NPDES Bioassessment, water chemistry 2002-2005

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Table 3: SWAMP sampling site locations. W = Water chemistry. T = Toxicity. B = Bioassessment (under SWAMP). N = Bioassessment (under non-SWAMP programs). P = Physical habitat.

Site Description Latitude (°N) Longitude (°E) W T B N P1 911TCWD10 Cottonwood Creek 10 32.5730 -116.7575 X X2 911TLAP04 La Posta Creek 4 32.7000 -116.4796 X X X X3 911TTET02 Tecate Creek 2 32.5654 -116.7585 X X4 911TTJR05 Tijuana River 5 32.5492 -117.0651 X X X5 911TJLCC2 Long Canyon Creek 2 32.7784 -116.4429 X X6 911TJPVC1 Pine Valley Creek 1 32.8357 -116.5432 X

Table 4. Non-SWAMP sampling site locations. W = sites where conventional water chemistry was sampled. B = sites where benthic macroinvertebrates were sampled.

Site Description

SWAMP site within

500 m Sources W B Lattitude (N) Longitude (E)1 Cottonwood Creek at Old Hwy 80 none Regional Board (911CCH80x) X 32.7880 -116.49762 Campo Creek at Hwy 94 Gauging Station none Regional Board (911CCH94x) X 32.5893 -116.5180

NPDES (CC-H94) X X3 Kitchen Creek at Cibbets Flat Campground none Regional Board (911KCBCFx) X 32.7606 -116.45164 Kitchen Creek at Kitchen Creek Road none Regional Board (911KCKCRx) X 32.7875 -116.45615 Long Canyon Creek at Cibbets Flat Campground 911TJLCC2 Regional Board (911LCCCFC) X 32.7783 -116.44506 La Posta Creek Narrows 911TLAP04 Regional Board (911LPCCTT) X 32.6999 -116.47917 Middle Cottonwood Creek below Morena Lake none Regional Board (911MCCBML) X 32.6758 -116.58318 North Pine Creek above Noble Creek none Regional Board (911NPCNCx, 911NPCRx) X 32.8652 -116.51839 Pine Creek upstream of Old Highway 80 none Regional Board (911PCH80x) X 32.8372 -116.5364

10 Troy Canyon Creek at Kitchen Creek Road none Regional Board (911TCCTCx) X 32.8078 -116.440011 Wilson Creek above Barrett Lake none Regional Board (911WLCABL) X 32.6936 -116.695312 Campo Creek in Campo none NPDES (CC-C) X X 32.6092 -116.440813 Wilson Creek at Lyons Valley Road (reference) none NPDES (REF-WC) X X 32.7075 -116.737214 Tijuana River at Dairy Mart Road 911TTJR05 NPDES (TJ-DM) X X 32.5469 -117.0624

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Figure 5. Sampling locations in the Tijuana HU. White circles represent sites sampled under SWAMP. Black circles represent sites sampled under non-SWAMP programs. Gray circles represent sites sampled under both SWAMP and non-SWAMP programs. The SWAMP site prefix designating the hydrologic unit (i.e., 911TJ-) has been dropped to improve clarity. 3.1 Indicators

Multiple indicators were used to assess the sites in the Tijuana HU. Water chemistry, water and sediment toxicity, benthic macroinvertebrate communities, and physical habitat.

3.1.1 Water chemistry To assess water chemistry, samples were collected at each site. Water chemistry was measured as per the SWAMP Quality Assurance Management Plan (QAMP) (Puckett 2002). Measured indicators included conventional water chemistry (e.g., pH, temperature dissolved oxygen, etc.), inorganics, herbicides, pesticides, polycyclic aromatic hydrocarbons (PAHs), dissolved metals, pesticides, and polychlorinated biphenyls (PCBs). Appendix II contains a complete list of constituents that were measured.

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Limited water chemistry was collected under non-SWAMP NPDES monitoring as well. This monitoring was restricted to physical parameters, and followed procedures described in annual reports to California Regional Water Quality Control Board, San Diego Region (e.g., Weston Solutions Inc. 2007). 3.1.2 Toxicity To evaluate water and sediment toxicity to aquatic life in the Tijuana HU, toxicity assays were conducted on samples from each site as per the SWAMP QAMP (EPA 1993, Puckett 2002). Water toxicity was evaluated with 7-day exposures on the water flea, Ceriodaphnia dubia, and 96-hour exposures to the alga Selenastrum capricornutum. Both acute and chronic toxicity to C. dubia was measured as decreased survival and fecundity (i.e., eggs per female) relative to controls, respectively. Chronic toxicity to S. capricornutum was measured as changes in total cell count relative to controls. Sediment toxicity was evaluated with 10-day exposures on the amphipod Hyallela azteca. Both acute and chronic toxicity to H. azteca was measured as decreased survival and growth (mg per individual) relative to controls, respectively. Chronic toxicity endpoints (i.e., C. dubia fecundity, H. azteca growth, and S. capricornutum total cell count) were used to develop a summary index of toxicity at each site. 3.1.3 Tissue Fish tissues were not assessed in the Tijuana HU. 3.1.4 Bioassessment To assess the ecological health of the streams in Tijuana HU, benthic macroinvertebrate samples were collected at 14 sites. Samples were collected using SWAMP-comparable protocols, as per the SWAMP QAMP (Puckett 2002). Three replicate samples were collected from riffles at each site; 300 individuals were sorted and identified from each replicate, creating a total count of 900 individuals per site. Using a Monte Carlo simulation, all samples were reduced to 500 count for calculation of the Southern California Index of Biotic Integrity (IBI; Ode et al. 2005), a composite of seven metrics summed and scaled from 0 (poor condition) to 100 (good condition). 3.1.5 Physical Habitat Physical habitat was assessed at La Posta Creek (LAP04) on April 16, 2007, using semi-quantitative observations of 10 components relating to habitat quality, such as embeddedness, bank stability, and width of riparian zone. The assessment protocols are described in The California Stream Bioassessment Procedure (California Department of Fish and Game 2003). Each component

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was scored on a scale of 0 (highly degraded) to 20 (not degraded). Sites were assessed by the average component score. 3.2 Data Analysis To evaluate the extent of human impacts to water chemistry in streams in the Tijuana HU, two frequency-based approaches were employed to detecting impacts. First, established aquatic life and human health thresholds for individual constituents were evaluated for frequency of exceedances. Second, the frequency of detection for anthropogenic constituents (such as PCBs, pesticides, and PAHs) were also evaluated. To evaluate the overall health of each site and of the watershed, three indicators were selected for analysis: number of constituents exceeding aquatic life water chemistry thresholds; frequency of chronic toxicity to S. capricornutum, C. dubia, and H. azteca; and mean IBI score. Physical habitat assessment was excluded due to lack of agreed-upon thresholds for evaluation of physical habitat scores. These results were plotted on a map of the watershed, indicating the severity and distribution of human impacts. Although non-SWAMP sources of water chemistry data were used, this report focuses on SWAMP data in order to maintain consistency of sampling methods and parameters measured at each site. Analyses of non-SWAMP water chemistry data is presented separately. In contrast, bioassessment data from multiple sources is analyzed together because of the high compatibility of sampling protocols used in different programs, and because of the limited availability of bioassessment data from a single source. Toxicity and physical habitat data were only available from SWAMP monitoring. 3.2.1 Thresholds In order to use the data to assess the health of the watershed, thresholds were established for each indicator: water quality, toxicity, bioassessment, and physical habitat. Exceedance of appropriate thresholds was considered evidence for impact on watershed health. Water chemistry data from this study were compared to water quality objectives established by state and federal agencies to protect the most sensitive beneficial uses designated in the Tijuana HU. Therefore, the most stringent water quality objectives (e.g., municipal drinking water, aquatic life, etc.) for the measured constituents were used as thresholds points to evaluate the data. The Water Quality Control Plan for the San Diego Basin (BP) was the primary source of water chemistry thresholds. Other sources for standards used in water chemistry thresholds included the California Toxics Rule (CTR), the

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Environmental Protection Agency National Aquatic Life Criteria (EPA), the National Academy of Sciences Health Advisory (NASHA), United States Environmental Protection Agency Integrated Risk Information System (IRIS), and the California Code of Regulations §64449 (CCR). The sources for thresholds used in this study are shown in Table 5. Table 5. Threshold sources Indicator Source Citation

Water chemistry Water Quality Control Plan For the San Diego Basin (BP)

California Regional Water Quality Control Board, San Diego Region. 1994. Water quality control plan for the San Diego Region. San Diego, CA. http://www.waterboards.ca.gov/sandiego/programs/basinplan.html

California Toxics Rule (CTR)

Environmental Protection Agency. 1997. Water quality standards: Establishment of numeric criteria for priority toxic pollutants for the state of California: Proposed Rule. Federal Register 62:42159-42208.

EPA National Aquatic Life Criteria (EPA)

Environmental Protection Agency. 2002. National recommended water quality criteria. EPA-822-R-02-047. Office of Water. Washington, DC.

National Academy of Sciences Health Advisory (NASHA)

National Academy of Sciences. 1977. Drinking Water and Health. Volume 1. Washington, DC.

US Environmental Protection Agency Integrated Risk Information System (IRIS)

Environmental Protection Agency (EPA). 2007. Integrated Risk Information System. http://www.epa.gov/iris/index.html. Office of Research and Development. Washington, DC.

California Code of Regulations §64449 (CCR)

California Code of Regulations. 2007. Secondary drinking water standards. Register 2007, No. 8. Title 22, division 4, article 16.

Bioassessment Ode et al. 2005 Ode, P.R., A.C. Rehn and J.T. May. 2005. A quantitative tool for assessing the integrity of southern California coastal streams. Environmental Management 35:493-504.

Although human health thresholds (e.g., drinking water standards) were applied to relevant water chemistry data, this report focuses on aquatic life, and does not address the risks to human health in the Tijuana HU. When multiple thresholds were applicable to a single constituent, the most stringent threshold was used. Water chemistry thresholds for aquatic life and human health standards used in this study are presented in Table 6. Impacts were assessed as the total number of constituents exceeding thresholds, as opposed to the fraction of constituents. The fraction of constituents exceeding thresholds is not an ecologically meaningful statistic because the number of constituents below thresholds does not degrade or improve the ecological health of a site.

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http://www.waterboards.ca.gov/sandiego/programs/basinplan.html

http://www.waterboards.ca.gov/sandiego/programs/basinplan.html

http://www.epa.gov/iris/index.html


Table 6. Water chemistry thresholds for aquatic life and human health standards. San Diego Basin Plan (BP); California Toxics Rule (CTR); Environmental Protection Agency National Aquatic Life Standards (EPA); National Academy of Science Health Advisory (NASHA); Environmental Protection Agency Integrated Risk Information System (IRIS); California Code of Regulations §64449 (CCR).

Category Constituent Applicability Threshold Unit Source Threshold Unit SourceInorganics Alkalinity as CaCO3 All sites 20000 mg/l EPA none mg/l noneInorganics Ammonia as N All sites 0.025 mg/l BP none mg/l noneInorganics Nitrate + Nitrite as N All sites 10 mg/l BP none mg/l noneInorganics Nitrate as NO3 Designated MUN only none mg/l none 45 mg/l BPInorganics Nitrite as N All sites none mg/l none 1 mg/l EPAInorganics Total N All sites 10:1 (TN:TP) or 1 mg/l BP none mg/l noneInorganics Phosphorus as P,Total All sites 0.1 mg/l BP none mg/l noneInorganics Selenium,Dissolved All sites 5 µg/L CTR none µg/L noneInorganics Sulfate All but HUC 911.1 250 mg/l BP none mg/l noneMetals Aluminum,Dissolved All sites 1000 µg/L BP none µg/L noneMetals Arsenic,Dissolved All sites 50 µg/L BP 150 µg/L CTRMetals Cadmium,Dissolved All sites 5 µg/L BP 2.2 µg/L CTRMetals Chromium,Dissolved All sites 50 µg/L BP none µg/L noneMetals Copper,Dissolved All sites 9 µg/L CTR 1300 µg/L CTRMetals Lead,Dissolved All sites 2.5 µg/L CTR none µg/L noneMetals Manganese,Dissolved All but HUC 911.1 0.05 mg/l BP none mg/l noneMetals Nickel,Dissolved All sites 52 µg/L CTR 610 µg/L CTRMetals Silver,Dissolved All sites 3.4 µg/L CTR none µg/L noneMetals Zinc,Dissolved All sites 120 µg/L CTR none µg/L nonePAHs Acenaphthene All sites none µg/L none 1200 µg/L CTRPAHs Anthracene All sites none µg/L none 9600 µg/L CTRPAHs Benz(a)anthracene All sites none µg/L none 0.0044 µg/L CTRPAHs Benzo(a)pyrene All sites 0.0002 µg/L BP 0.0044 µg/L CTRPAHs Benzo(b)fluoranthene All sites none µg/L none 0.0044 µg/L CTRPAHs Benzo(k)fluoranthene All sites none µg/L none 0.0044 µg/L CTRPAHs Chrysene All sites none µg/L none 0.0044 µg/L CTRPAHs Dibenz(a,h)anthracene All sites none µg/L none 0.0044 µg/L CTRPAHs Fluoranthene All sites none µg/L none 300 µg/L CTRPAHs Indeno(1,2,3-c,d)pyrene All sites none µg/L none 0.0044 µg/L CTRPAHs Pyrene All sites none µg/L none 960 µg/L CTRPCBs PCBs All sites 0.014 µg/L CTR 0.00017 µg/L CTRPesticides Aldrin All sites 3 µg/L CTR 0.00000013 µg/L CTRPesticides Alpha-BHC All sites none µg/L none 0.0039 µg/L CTRPesticides Beta-BHC All sites none µg/L none 0.014 µg/L CTRPesticides Gamma-BHC (Lindane) All sites 0.95 µg/L CTR 0.019 µg/L CTRPesticides Ametryn All sites none µg/L none 60 µg/L EPAPesticides Atrazine All sites 3 µg/L BP 0.2 µg/L OEHHAPesticides Azinphos ethyl All sites none µg/L none 87.5 µg/L NASHAPesticides Azinphos methyl All sites none µg/L none 87.5 µg/L NASHAPesticides Chlordanes All sites 0.0043 µg/L CTR 0.00057 µg/L CTRPesticides DDD(p,p') All sites none µg/L none 0.00083 µg/L CTRPesticides DDE(p,p') All sites none µg/L none 0.00059 µg/L CTRPesticides DDT(p,p') All sites none µg/L none 0.00059 µg/L CTRPesticides Dieldrin All sites none µg/L none 0.00014 µg/L CTRPesticides Dimethoate All sites none µg/L none 1.4 µg/L IRISPesticides Endosulfan sulfate All sites none µg/L none 110 µg/L CTRPesticides Endrin All sites 0.002 µg/L BP 0.76 µg/L CTRPesticides Endrin Ketone All sites none µg/L none 0.85 µg/L CTRPesticides Heptachlor All sites 0.0038 µg/L CTR 0.00021 µg/L CTRPesticides Heptachlor epoxide All sites 0.0038 µg/L CTR 0.0001 µg/L CTRPesticides Hexachlorobenzene All sites 1 µg/L BP 0.00075 µg/L CTR

Aquatic life Human health

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Table 6, continued. Water chemistry thresholds for aquatic life and human health.

Category Constituent Applicability Threshold Unit Source Threshold Unit SourcePesticides Methoxychlor All sites 40 µg/L BP none µg/L nonePesticides Molinate All sites 20 µg/L BP none µg/L nonePesticides Oxychlordane All sites none µg/L none 0.000023 µg/L CTRPesticides Simazine All sites 4 µg/L BP none µg/L nonePesticides Thiobencarb All sites 70 µg/L BP none µg/L nonePesticides Toxaphene All sites 0.0002 µg/L CTR 0.0002 µg/L CTRPhysical Oxygen, Dissolved Designated WARM only 5 mg/L BP none mg/L nonePhysical Oxygen, Dissolved Designated COLD only 6 mg/L BP none mg/L nonePhysical pH All sites >6 and <8 pH BP none pH nonePhysical Specific Conductivity All sites 1600 μS/cm CCR none mS/cm nonePhysical Turbidity All but HUC 911.1 20 NTU BP none NTU none

Aquatic life Human health

Several anthropogenic water chemistry constituents had no applicable threshold (e.g., malathion), and impacts from these constituents would not be detected using the threshold-based approach described above. To assess the impact from these constituents, the number of organic constituents (i.e., PAHs, PCBs, and pesticides) detected at each site were calculated. The total number of sites at which these compounds were detected was recorded.

Thresholds for toxicity assays were determined by comparing study

samples to control samples (non-toxic reference samples). Samples meeting the following criteria were considered toxic: 1) treatment responses significantly different from controls, as determined by a statistical t-test; and 2) endpoints less than 80% of controls. To summarize the toxicity at a site using multiple endpoints, the frequency of toxic samples was calculated. To assign equal weight to all three indicators, a single endpoint of chronic toxicity per indicator was used (C. dubia: fecundity, H. azteca: growth, and S. capricornutum: total cell count).

Thresholds for bioassessment samples were based on a benthic macroinvertebrate index of biological integrity (IBI) that was developed specifically for southern California (Ode et al. 2005). The results of the IBI produces a measure of impairment with scores scaled from 0 to 100, 0 representing the poorest health and 100 the best health. Based on the IBI, samples with scores equal to or below 40 are considered to be in “poor” condition, and samples below 20 are considered to be in “very poor” condition. Therefore, in this study samples with an IBI below 40 were considered impacted. Thresholds for the evaluation of physical habitat have not been established. Therefore, measurements of physical habitat were excluded from the overall assessment of ecological health. However, because the protocol used to evaluate physical habitat qualitatively assigns scores lower than 10 (out of 20) to streams in poor condition, this number was used to determine sites with severely degraded habitat. Sites with scores below 15 were considered moderately degraded, and those with scores greater than 15 were considered unimpacted (California Department of Fish and Game 2003).

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3.2.2 Quality Assurance and Quality Control (QA/QC) The SWAMP QAMP guided QA/QC for all data collected under SWAMP (See SWAMP QAMP for detailed descriptions of QA/QC protocols, Puckett 2002). QA/QC officers flagged non-compliant physical habitat, water chemistry, and toxicity. No chemistry or toxicity data were excluded as a result of QA/QC violations. QA/QC procedures for NPDES water chemistry data were similar to those used in SWAMP (Weston Solutions Inc. 2007) Non-SWAMP bioassessment samples were screened for samples containing fewer than 450 individuals. No bioassessment sample was excluded from this analysis.

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4. RESULTS 4.1 Water Chemistry Analysis of water chemistry at SWAMP sites indicated widespread and severe impacts throughout the watershed, although impacts were more severe in streams flowing from Mexico (Tecate Creek—TET02, and the Tijuana River mainstem—TJR05) than for watersheds entirely within the United States (Cottonwood Creek—CWD10, and La Posta Creek—LAP04). Across the entire watershed, 45 PAHs were detected, but none in watersheds entirely within the United States. All 45 were detected in the Tijuana River, and slightly more than half (i.e., 26) were detected in Tecate Creek. Of the 48 PAHs analyzed, all but 3 (i.e., dichlofenthion, C2-fluorenes, and c3-fluorenes) were detected at the Tijuana River. Analysis of pesticides shows a similar (but less severe) pattern of impact: 5 pesticides were detected in Tecate Creek, and 3 were detected in the Tijuana River, but only one (i.e., diazinon) was detected in watersheds entirely within the United States. This pesticide was found at every site in the HU. No PCBs were detected at any site. Means and standard deviations of all constituents are presented in Appendix II.

Table 7. Number of anthropogenic organic compounds detected at each site in Tijuana HU.

PAHs PCBs PesticidesSite Tested Detected Tested Detected Tested Detected911TCWD10 48 0 50 0 79 1911TLAP04 48 0 50 0 79 1911TTET02 48 26 50 0 79 5911TTJR05 48 45 50 0 79 3All sites 48 45 50 0 79 5

Apart from diazinon, all anthropogenic organic constituents were restricted to streams draining Mexico. All PAHs detected in Tecate Creek were also detected in the Tijuana River, and all pesticides detected in the Tijuana River were also found in Tecate Creek (Table 8). This distribution may reflect the strength of industrial sources of PAHs at the Tijuana River site and agricultural sources of pesticides at the Tecate Creek site.

Table 8. Frequency of detection of anthropogenic organic compounds in the Tijuana HU. Constituent not detected at any site (--). Category Constituent Sites tested Sites detected FrequencyPAHs Acenaphthene 4 1 0.25PAHs Acenaphthylene 4 1 0.25PAHs Anthracene 4 1 0.25PAHs Benz(a)anthracene 4 1 0.25

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Table 8, continued. Frequency of detection of anthropogenic organic compounds. Category Constituent Sites tested Sites detected FrequencyPAHs Benzo(b)fluoranthene 4 1 0.25PAHs Benzo(e)pyrene 4 1 0.25PAHs Benzo(g,h,i)perylene 4 1 0.25PAHs Benzo(k)fluoranthene 4 1 0.25PAHs Biphenyl 4 2 0.50PAHs Chrysene 4 1 0.25PAHs Chrysenes, C1 - 4 1 0.25PAHs Chrysenes, C2 - 4 2 0.50PAHs Chrysenes, C3 - 4 1 0.25PAHs Dibenz(a,h)anthracene 4 1 0.25PAHs Dibenzothiophene 4 2 0.50PAHs Dibenzothiophenes, C1 - 4 2 0.50PAHs Dibenzothiophenes, C2 - 4 2 0.50PAHs Dibenzothiophenes, C3 - 4 2 0.50PAHs Dichlofenthion 4 0 --PAHs Dimethylnaphthalene, 2,6- 4 2 0.50PAHs Dimethylphenanthrene, 3,6- 4 2 0.50PAHs Fluoranthene 4 2 0.50PAHs Fluoranthene/Pyrenes, C1 - 4 2 0.50PAHs Fluorene 4 2 0.50PAHs Fluorenes, C1 - 4 2 0.50PAHs Fluorenes, C2 - 4 0 --PAHs Fluorenes, C3 - 4 0 --PAHs Indeno(1,2,3-c,d)pyrene 4 1 0.25PAHs Methyldibenzothiophene, 4- 4 2 0.50PAHs Methylfluoranthene, 2- 4 1 0.25PAHs Methylfluorene, 1- 4 2 0.50PAHs Methylnaphthalene, 1- 4 1 0.25PAHs Methylnaphthalene, 2- 4 1 0.25PAHs Methylphenanthrene, 1- 4 2 0.50PAHs Naphthalene 4 1 0.25PAHs Naphthalenes, C1 - 4 2 0.50PAHs Naphthalenes, C2 - 4 2 0.50PAHs Naphthalenes, C3 - 4 2 0.50PAHs Naphthalenes, C4 - 4 2 0.50PAHs Perylene 4 1 0.25PAHs Phenanthrene 4 2 0.50PAHs Phenanthrene/Anthracene, C1 - 4 2 0.50PAHs Phenanthrene/Anthracene, C2 - 4 2 0.50PAHs Phenanthrene/Anthracene, C3 - 4 2 0.50PAHs Phenanthrene/Anthracene, C4 - 4 2 0.50PAHs Pyrene 4 2 0.50PAHs Trimethylnaphthalene, 2,3,5- 4 2 0.50PCBs PCB 005 4 0 --PCBs PCB 008 4 0 --PCBs PCB 015 4 0 --PCBs PCB 018 4 0 --PCBs PCB 027 4 0 --PCBs PCB 028 4 0 --

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Table 8, continued. Frequency of detection of anthropogenic organic compounds. Category Constituent Sites tested Sites detected FrequencyPCBs PCB 029 4 0 --PCBs PCB 031 4 0 --PCBs PCB 033 4 0 --PCBs PCB 044 4 0 --PCBs PCB 049 4 0 --PCBs PCB 052 4 0 --PCBs PCB 056 4 0 --PCBs PCB 060 4 0 --PCBs PCB 066 4 0 --PCBs PCB 070 4 0 --PCBs PCB 074 4 0 --PCBs PCB 087 4 0 --PCBs PCB 095 4 0 --PCBs PCB 097 4 0 --PCBs PCB 099 4 0 --PCBs PCB 101 4 0 --PCBs PCB 105 4 0 --PCBs PCB 110 4 0 --PCBs PCB 114 4 0 --PCBs PCB 118 4 0 --PCBs PCB 128 4 0 --PCBs PCB 137 4 0 --PCBs PCB 138 4 0 --PCBs PCB 141 4 0 --PCBs PCB 149 4 0 --PCBs PCB 151 4 0 --PCBs PCB 153 4 0 --PCBs PCB 156 4 0 --PCBs PCB 157 4 0 --PCBs PCB 158 4 0 --PCBs PCB 170 4 0 --PCBs PCB 174 4 0 --PCBs PCB 177 4 0 --PCBs PCB 180 4 0 --PCBs PCB 183 4 0 --PCBs PCB 187 4 0 --PCBs PCB 189 4 0 --PCBs PCB 194 4 0 --PCBs PCB 195 4 0 --PCBs PCB 200 4 0 --PCBs PCB 201 4 0 --PCBs PCB 203 4 0 --PCBs PCB 206 4 0 --PCBs PCB 209 4 0 --Pesticides Aldrin 4 0 --Pesticides Aspon 4 0 --Pesticides Azinphos ethyl 4 0 --Pesticides Azinphos methyl 4 0 --Pesticides Bolstar 4 0 --

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Table 8, continued. Frequency of detection of anthropogenic organic compounds. Category Constituent Sites tested Sites detected FrequencyPesticides Carbophenothion 4 0 --Pesticides Chlordane, cis- 4 0 --Pesticides Chlordane, trans- 4 0 --Pesticides Chlordene, alpha- 4 0 --Pesticides Chlordene, gamma- 4 0 --Pesticides Chlorfenvinphos 4 0 --Pesticides Chlorpyrifos 4 1 0.25Pesticides Chlorpyrifos methyl 4 0 --Pesticides Ciodrin 4 0 --Pesticides Coumaphos 4 0 --Pesticides Dacthal 4 0 --Pesticides DDD(o,p') 4 0 --Pesticides DDD(p,p') 4 0 --Pesticides DDE(o,p') 4 0 --Pesticides DDE(p,p') 4 0 --Pesticides DDMU(p,p') 4 0 --Pesticides DDT(o,p') 4 0 --Pesticides DDT(p,p') 4 0 --Pesticides Demeton-s 4 0 --Pesticides Diazinon 4 4 1.00Pesticides Dichlorvos 4 0 --Pesticides Dicrotophos 4 0 --Pesticides Dieldrin 4 0 --Pesticides Dimethoate 4 0 --Pesticides Dioxathion 4 2 0.50Pesticides Disulfoton 4 2 0.50Pesticides Endosulfan I 4 0 --Pesticides Endosulfan II 4 0 --Pesticides Endosulfan sulfate 4 0 --Pesticides Endrin 4 0 --Pesticides Endrin Aldehyde 4 0 --Pesticides Endrin Ketone 4 0 --Pesticides Ethion 4 0 --Pesticides Ethoprop 4 0 --Pesticides Famphur 4 0 --Pesticides Fenchlorphos 4 0 --Pesticides Fenitrothion 4 0 --Pesticides Fensulfothion 4 0 --Pesticides Fenthion 4 0 --Pesticides Fonofos 4 1 0.25Pesticides HCH, alpha 4 0 --Pesticides HCH, beta 4 0 --Pesticides HCH, delta 4 0 --Pesticides HCH, gamma 4 0 --Pesticides Heptachlor 4 0 --Pesticides Heptachlor epoxide 4 0 --Pesticides Hexachlorobenzene 4 0 --Pesticides Leptophos 4 0 --Pesticides Malathion 4 0 --

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Table 8, continued. Frequency of detection of anthropogenic organic compounds. Category Constituent Sites tested Sites detected FrequencyPesticides Merphos 4 0 --Pesticides Methidathion 4 0 --Pesticides Methoxychlor 4 0 --Pesticides Mevinphos 4 0 --Pesticides Mirex 4 0 --Pesticides Molinate 4 0 --Pesticides Naled 4 0 --Pesticides Nonachlor, cis- 4 0 --Pesticides Nonachlor, trans- 4 0 --Pesticides Oxadiazon 4 0 --Pesticides Oxychlordane 4 0 --Pesticides Parathion, Ethyl 4 0 --Pesticides Parathion, Methyl 4 0 --Pesticides Phorate 4 0 --Pesticides Phosmet 4 0 --Pesticides Phosphamidon 4 0 --Pesticides Sulfotep 4 0 --Pesticides Tedion 4 0 --Pesticides Terbufos 4 0 --Pesticides Tetrachlorvinphos 4 0 --Pesticides Thiobencarb 4 0 --Pesticides Thionazin 4 0 --Pesticides Tokuthion 4 0 --Pesticides Trichlorfon 4 0 --Pesticides Trichloronate 4 0 --

Comparison with applicable aquatic life and human health thresholds

support the conclusion that water quality is impacted by a number of water chemistry constituents (Table 9, Figures 6, 7). Although differences between streams entering from Mexico and streams within the United States were evident, these differences were moderate. For example, streams receiving water from Mexico exceeded only a few more aquatic life thresholds than streams entirely within the United States, in contrast to the large differences observed in Table 8.

The identity of constituents exceeding thresholds varied from site to site,

although a few constituents were impacted at multiple sites. For example, nutrients (particularly ammonia-N), selenium, and magnesium exceeded thresholds at a majority of sites, and half the sites did not meet standards for pH and dissolved oxygen (Table 10). Exceedances ranged from a low of 3 at La Posta Creek to a high of 8 at the Tijuana River mainstem (Table 11). Furthermore, all human health threshold exceedances were restricted to this site, where 7 constituents (all PAHs) exceeded thresholds (Table 11).

Water chemistry was minimally impacted at La Posta Creek, where only

three constituents exceeded aquatic life thresholds: ammonia-N, total nitrogen, and dissolved oxygen. Furthermore, these exceedances were observed on a single sampling date, suggesting that these impacts were transient and that

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water chemistry was in good condition most of the time. In contrast, several constituents exceeded thresholds on all sampling dates at the other sites (Table 9).

Results from NPDES water chemistry monitoring at 4 sites suggested low

levels of impact, although very few constituents were assessed at these sites (Table 9C). Dissolved oxygen, specific conductivity, and pH exceeded aquatic life thresholds at these sites, but never more than once at an individual site. Turbidity did not exceed applicable thresholds at site 2 (Campo Creek).

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Table 9. Frequency of water chemistry threshold exceedances. A) Frequency of aquatic life threshold exceedances at SWAMP sites. B) Frequency of human health threshold exceedances at SWAMP sites. C) Frequency of aquatic life threshold exceedances at non-SWAMP sites. No human health thresholds applied to constituents measured at non-SWAMP sites. Freq = Frequency of samples exceeding applicable thresholds at each site. AL = Aquatic life. HH = Human health. -- = Constituent never exceeded threshold. NA = No applicable thresholds at that site. Empty cells indicate that the constituent was not measured at the site. A. Aquatic life thresholds at SWAMP sites.

911TCWD10 911TLAP04 911TTET02 911TTJR05Category Constituent Freq n Freq n Freq n Freq nInorganics Alkalinity as CaCO3 -- 2 -- 4 -- 4 -- 2Inorganics Ammonia as N 1.00 2 0.25 4 1.00 4 1.00 2Inorganics Phosphorus as P,Total 0.50 2 -- 4 1.00 4 1.00 2Inorganics Selenium,Dissolved 1.00 2 -- 4 1.00 4 1.00 2Inorganics Sulfate -- 2 -- 4 -- 4 NA 0Inorganics Total N -- 2 0.25 4 -- 4 -- 2Metals Aluminum,Dissolved -- 2 -- 4 -- 4 -- 2Metals Arsenic,Dissolved -- 2 -- 4 -- 4 -- 2Metals Cadmium,Dissolved -- 2 -- 4 -- 4 -- 2Metals Chromium,Dissolved -- 2 -- 4 -- 4 -- 2Metals Copper,Dissolved -- 2 -- 4 -- 4 0.50 2Metals Lead,Dissolved -- 2 -- 4 -- 4 -- 2Metals Manganese,Dissolved 0.50 2 -- 4 1.00 4 NA 2Metals Nickel,Dissolved -- 2 -- 4 -- 4 -- 2Metals Silver,Dissolved -- 2 -- 4 -- 4 -- 2Metals Zinc,Dissolved -- 2 -- 4 -- 4 -- 2PAHs Benzo(a)pyrene -- 2 -- 4 -- 4 0.50 2PCBs PCBs -- 2 -- 4 -- 4 -- 2Pesticides Chlordanes -- 2 -- 4 -- 4 -- 2Pesticides Endrin -- 2 -- 4 -- 4 -- 2Pesticides Heptachlor -- 2 -- 4 -- 4 -- 2Pesticides Heptachlor epoxide -- 2 -- 4 -- 4 -- 2Pesticides Hexachlorobenzene -- 2 -- 4 -- 4 -- 2Pesticides Methoxychlor -- 2 -- 4 -- 4 -- 2Pesticides Molinate -- 2 -- 4 -- 4 -- 2Pesticides Thiobencarb -- 2 -- 4 -- 4 -- 2Physical Oxygen, Dissolved -- 2 0.25 4 0.50 4 -- 2Physical pH 0.50 2 -- 4 -- 4 1.00 2Physical Specific conductivity -- 2 -- 4 1.00 4 0.50 2Physical Turbidity -- 2 -- 4 0.75 4 NA 0

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Table 9, continued. Frequency of water chemistry threshold exceedances. B. Human health thresholds at SWAMP sites

911TCWD10 911TLAP04 911TTET02 911TTJR05Category Constituent Freq n Freq n Freq n Freq nInorganics Nitrate + Nitrite as N -- 2 -- 4 -- 4 -- 2Inorganics Nitrate as NO3 -- 2 -- 4 -- 4 NA 2Inorganics Nitrite as N -- 2 -- 4 -- 4 -- 2Metals Arsenic,Dissolved -- 2 -- 4 -- 4 -- 2Metals Cadmium,Dissolved -- 2 -- 4 -- 4 -- 2Metals Copper,Dissolved -- 2 -- 4 -- 4 -- 2Metals Nickel,Dissolved -- 2 -- 4 -- 4 -- 2PAHs Acenaphthene -- 2 -- 4 -- 4 -- 2PAHs Anthracene -- 2 -- 4 -- 4 -- 2PAHs Benz(a)anthracene -- 2 -- 4 -- 4 0.5 2PAHs Benzo(a)pyrene -- 2 -- 4 -- 4 0.5 2PAHs Benzo(b)fluoranthene -- 2 -- 4 -- 4 0.5 2PAHs Benzo(k)fluoranthene -- 2 -- 4 -- 4 0.5 2PAHs Chrysene -- 2 -- 4 -- 4 0.5 2PAHs Dibenz(a,h)anthracene -- 2 -- 4 -- 4 0.5 2PAHs Fluoranthene -- 2 -- 4 -- 4 -- 2PAHs Indeno(1,2,3-c,d)pyrene -- 2 -- 4 -- 4 0.5 2PAHs Pyrene -- 2 -- 4 -- 4 -- 2PCBs PCBs -- 2 -- 4 -- 4 -- 2Pesticides Aldrin -- 2 -- 4 -- 4 -- 2Pesticides Azinphos ethyl -- 2 -- 4 -- 4 -- 2Pesticides Azinphos methyl -- 2 -- 4 -- 4 -- 2Pesticides Chlordanes -- 2 -- 4 -- 4 -- 2Pesticides DDD(p,p') -- 2 -- 4 -- 4 -- 2Pesticides DDE(p,p') -- 2 -- 4 -- 4 -- 2Pesticides DDT(p,p') -- 2 -- 4 -- 4 -- 2Pesticides Dieldrin -- 2 -- 4 -- 4 -- 2Pesticides Dimethoate -- 2 -- 4 -- 4 -- 2Pesticides Endosulfan sulfate -- 2 -- 4 -- 4 -- 2Pesticides Endrin -- 2 -- 4 -- 4 -- 2Pesticides Endrin Aldehyde -- 2 -- 4 -- 4 -- 2Pesticides Endrin Ketone -- 2 -- 4 -- 4 -- 2Pesticides Heptachlor -- 2 -- 4 -- 4 -- 2Pesticides Heptachlor epoxide -- 2 -- 4 -- 4 -- 2Pesticides Hexachlorobenzene -- 2 -- 4 -- 4 -- 2Pesticides Oxychlordane -- 2 -- 4 -- 4 -- 2

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Table 9, continued. Frequency of water chemistry threshold exceedances. C. Aquatic life thresholds at non-SWAMP sites.

Site 2 (CC-H94) Site 11 (REF-WC) Site 12 (CC-C) Site 14 (TJ-DM)

Constituent Frequency n Frequency n Frequency n Frequency nDissolved oxygen 1.00 1 -- 1 0.33 3 0.50 2pH -- 1 1.00 1 -- 3 -- 2Specific conductivity 1.00 1 -- 1 -- 3 0.50 2Turbidity -- 1 n.t. 0 n.t. 0 NA 1 Table 10. Frequency of SWAMP sites with aquatic life and human health threshold exceedances for each constituent. Number of SWAMP sites included in evaluation (n). Constituent never exceeded threshold at any site (--). No applicable threshold for constituent (NA).

Category Constituent Aquatic life Human health nInorganics Alkalinity as CaCO3 -- NA 4Inorganics Ammonia as N 1.00 NA 4Inorganics Nitrate + Nitrite as N NA -- 4Inorganics Nitrate as NO3 NA -- 4Inorganics Nitrite as N NA -- 4Inorganics Phosphorus as P,Total 0.75 NA 4Inorganics Selenium,Dissolved 0.75 NA 4Inorganics Sulfate -- NA 3Inorganics Total N 0.25 NA 4Metals Aluminum,Dissolved -- NA 4Metals Arsenic,Dissolved -- -- 4Metals Cadmium,Dissolved -- -- 4Metals Chromium,Dissolved -- NA 4Metals Copper,Dissolved 0.25 -- 4Metals Lead,Dissolved -- NA 4Metals Manganese,Dissolved 0.67 NA 3Metals Nickel,Dissolved -- -- 4Metals Silver,Dissolved -- NA 4Metals Zinc,Dissolved -- NA 4PAHs Acenaphthene NA -- 4PAHs Anthracene NA -- 4PAHs Benz(a)anthracene NA -- 4PAHs Benzo(a)pyrene 0.25 -- 4PAHs Benzo(b)fluoranthene NA -- 4PAHs Benzo(k)fluoranthene NA -- 4PAHs Chrysene NA -- 4PAHs Dibenz(a,h)anthracene NA -- 4PAHs Fluoranthene NA -- 4PAHs Indeno(1,2,3-c,d)pyrene NA -- 4PAHs Pyrene NA -- 4PCBs PCBs -- -- 4Pesticides Aldrin NA -- 4Pesticides Azinphos ethyl NA -- 4Pesticides Azinphos methyl NA -- 4Pesticides Chlordanes -- -- 4

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Table 10, continued. Frequency of SWAMP sites with aquatic life and human health threshold exceedances.

Category Constituent Aquatic life Human health nPesticides DDD(p,p') NA -- 4Pesticides DDE(p,p') NA -- 4Pesticides DDT(p,p') NA -- 4Pesticides Dieldrin NA -- 4Pesticides Dimethoate NA -- 4Pesticides Endosulfan sulfate NA -- 4Pesticides Endrin -- -- 4Pesticides Endrin Aldehyde NA -- 4Pesticides Endrin Ketone NA -- 4Pesticides Heptachlor -- -- 4Pesticides Heptachlor epoxide -- -- 4Pesticides Hexachlorobenzene -- -- 4Pesticides Methoxychlor -- NA 4Pesticides Molinate -- NA 4Pesticides Oxychlordane NA -- 4Pesticides Thiobencarb -- NA 4Physical Oxygen, Dissolved 0.50 NA 4Physical pH 0.50 NA 4Physical Specific conductivity 0.50 NA 4Physical Turbidity 0.33 NA 3

Table 11. Number of constituents exceeding thresholds at each SWAMP site.

Aquatic life Human health# exceedances # tests # exceedances # tests

911TCWD10 5 30 0 36911TLAP04 3 30 0 36911TTET02 7 30 0 36911TTJR05 7 27 7 36All sites in watershed 11 30 7 36

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Figure 6. Map of aquatic life threshold exceedances for water chemistry at SWAMP sites. White circles indicate sites with one or fewer exceedances (this value did not occur in this watershed). Pink circles indicate sites with 2 to 5 exceedances. Red circles indicate sites with 6 to 9 exceedances. At the Tijuana River mainstem (TJR05), 27 constituents were assessed; at all other sites, 30 constituents were assessed.

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Figure 7. Map of human health exceedances for water chemistry at SWAMP sites. White circles indicate sites with one or fewer exceedances. Pink circles indicate sites with 2 to 5 exceedances. Red circles indicate sites with 6 to 9 exceedances (this value did not occur in this watershed). At all sites, 36 constituents were assessed.

4.2 Toxicity

Toxicity was evident at all sites within the watershed, although results varied among sites and indicators (Table 12; Appendix III). Furthermore, uneven effort among sites hamper meaningful comparisons of results across the HU. Toxicity was most severe at Tecate Creek and the mainstem Tijuana River, where every sample caused toxicity to the crustacean H. azteca (for both lethal and sub-lethal endpoints) and to the alga S. capricornutum (assessed only at Tecate Creek). In contrast, toxicity was less severe at Cottonwood and La Posta Creeks, where lethal toxicity was never observed. Furthermore, one sample from La Posta Creek did not cause toxicity to the crustacean C. dubia (Figure 8).

The crustacean H. azteca was a very sensitive indicator of toxicity in the

Tijuana HU. However, too few assays using other species (i.e. one assay using C. dubia and two assays using S. capricornutum) were conducted to evaluate the relative sensitivity of these indicators.

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Table 12. Frequency of toxicity detected for each endpoint and at each site. A sample was considered toxic if the response was less than 80% of the control sample, and the difference was considered significant at P<0.05. Number of samples where the endpoint was evaluated (n). Toxicity not detected in any sample (--). Endpoint not tested (nt).

C. dubia H. azteca S. capricornutum MultipleSampling Survival Young / Female Survival Growth Total cell count indicators

Site events Frequency n Frequency n Frequency n Frequency n Frequency n Frequency n911TCWD10 1 nt 0 nt 0 -- 1 1.00 1 nt 0 1.00 1911TLAP04 4 -- 1 -- 1 -- 3 1.00 3 1.00 1 0.80 5911TTET02 2 nt 0 nt 0 1.00 2 1.00 1 1.00 1 1.00 2911TTJR05 2 nt 0 nt 0 1.00 2 1.00 2 nt 0 1.00 2All sites in watershed 9 -- 1 -- 1 0.50 8 1.00 7 1.00 2 0.90 10

Figure 8. Frequency of toxicity (C. dubia fecundity, H. azteca growth, and S. capricornutum total cell count) at SWAMP sites. White circles indicate low frequency (0.0 to 0.1) of toxicity (this value did not occur in this watershed) . Pink circles indicate moderate frequency (0.1 to 0.5) of toxicity. Red circles indicate high (0.5 to 1.0) frequency of toxicity (this value did not occur in this watershed).

4.3 Tissue

Fish tissues were not analyzed in the Tijuana HU.

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4.4 Bioassessment

Biological health ranged from good to very poor at sites in the Tijuana HU. Mean IBI scores ranged from 8.6 at the mainstem of the Tijuana River to a high of 70.0 at Pine Valley Creek (Table 13; Figure 9). Sites in fair or good condition were concentrated in the upper Cottonwood Creek watershed above Morena Reservoir, where all 5 sites assessed had mean IBIs between 40 and 60 (Figure 9). Of the 15 sites where bioassessment samples were collected, samples in poor condition were observed at 8. Samples from 7 sites (i.e., Los Coches Creek (LCC2), Pine Valley Creek (PVC1), and sites 1, 3, 4, 9, and 13) were never in poor or very poor condition.

Although most sites in the northern part of the watershed were in better

biological condition, a few sites contrasted with this pattern. For example, site 8 (north Pine Valley Creek) was in poor condition, although samples collected further downstream were in fair condition. In addition, samples from Cottonwood Creek below Morena Lake (site 7), Wilson Creek above Barrett Lake (site 11), and La Posta Creek (LAP04) were also in poor condition, with mean IBIs below 40. However, at two of these sites (i.e., site 7 and La Posta Creek), samples in fair biological condition were sometimes observed.

Some of the metrics that make up the IBI were very sensitive to

degradation. For example, some metrics (e.g., % Collectors, EPT Taxa, and % Intolerant) made large contributions to IBI scores at sites in good condition, but small contributions at sites in poor condition. In contrast, other metrics (e.g., Predator Taxa) had a weaker relationship with the overall IBI score (Appendix IV; Figure 10).

Examination of IBI scores over time did not indicate a trend towards

improving or deteriorating biological condition (Figure 11). Variability among years was high, which may obscure trends in the data. Seasonal trends were not apparent (Figures 11, 12).

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Table 13. Mean and standard deviation of IBI scores at bioassessment sites within the Tijuana HU. Number of samples collected within each season (n). Range from first to last year of sampling at each site (Years). Frequency of poor or very poor IBI scores (IBI <40) at each site and season (Frequency).

IBISite Season n Years Mean SD Condition Frequency911TLAP04 Average 5 2000-2005 30.0 4.0 Poor 0.60

Fall 2 2000-2005 32.9 10.1 Poor 0.50Spring 3 2001-2005 27.1 15.1 Poor 0.67

911TTJR05 Spring 1 2003 8.6 Very poor 1.00911TJLCC2 Spring 2 2001-2006 58.6 20.2 Fair --911TJPVC1 Spring 1 2006 70.0 Good --Site 1 Average 6 2000-2005 53.3 2.6 Fair --

Fall 1 2000 51.4 Fair --Spring 5 2000-2005 55.1 8.5 Fair --

Site 2 Average 3 2000-2003 37.1 14.1 Poor 0.67Fall 1 2000 47.1 Fair --Spring 2 2001-2003 27.1 14.1 Poor 1.00

Site 3 Spring 1 2001 60.0 Good --Site 4 Spring 1 2001 60.0 Good --Site 7 Average 2 1999-2001 35.0 23.2 Poor 0.50

Fall 1 1999 51.4 Fair --Spring 1 2001 18.6 Very poor 1.00

Site 8 Spring 6 2001-2005 38.3 13.3 Poor 0.50Site 9 Average 5 1999-2005 55.2 5.4 Fair --

Fall 3 1999-2005 59.0 12.1 Fair --Spring 2 2000-2001 51.4 16.2 Fair --

Site 10 Average 5 2000-2005 47.3 16.4 Fair 0.20Fall 1 2000 35.7 Poor 1.00Spring 4 2000-2005 58.9 8.6 Fair --

Site 11 Spring 1 2001 32.9 Poor 1.00Site 12 Average 3 2004-2005 11.1 3.5 Very poor 1.00

Fall 1 2004 8.6 Very poor 1.00Spring 2 2004-2005 13.6 11.1 Very poor 1.00

Site 13 Spring 1 2005 51.4 Fair --

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Figure 9. IBI scores at sites in the Tijuana HU. White circles indicate good or very good (60 to 100) IBI scores (this value did not occur in this watershed). Pink circles indicate fair (40 to 60) IBI scores (this value did not occur in this watershed). Red circles indicate poor (0 to 40) IBI scores. Open circles represent 500-m buffers around SWAMP sites; six of these buffers included bioassessment sites, and three of these buffers did not.

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Figure 10. Mean IBI scores at each bioassessment site and each season. The height of the bar indicates the mean IBI score, and the size of each component of the bar represents the contribution of each metric to the IBI.

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Figure 11. IBI values for each year and site. Each symbol represents a single sample.

4.5 Physical Habitat

Physical habitat was moderately degraded at La Posta Creek, which had a mean physical habitat score of 13.0. However, most components of physical habitat showed minimal signs of degradation (score ≥ 15). Instream cover was sparse, and received a score of 10, indicating moderate degradation. Three components of physical habitat (i.e., embeddedness, velocity-depth regime, and sediment deposition) were severely degraded, with scores below 10, (Table 14; Figure 12).

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Table 14. Score and mean for each component of physical habitat at La Posta Creek (LAP04) measured on April 16, 2007. Component range: 0 (heavily impacted habitat) to 20 (unimpacted habitat).

Physical habitat component Score1 Epifaunal cover 102 Embeddedness 33 Velocity-depth regime 94 Sediment deposition 55 Channel flow 186 Channel alteration 197 Riffle frequency 168 Bank stability 169 Vegetation protection 15

10 Riparian zone 19Mean physical habitat score 13.0

Figure 12. Assessment of physical habitat at SWAMP sites. White circles indicate sites with a mean physical habitat scores between 15 and 20. Pink circles indicate mean scores between 10 and 15. Red circles indicate mean scores between 0 and 10.

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5. DISCUSSION Every site sampled in the Tijuana HU showed evidence of impact from

multiple indicators, although impacts at individual sites ranged from moderate to severe (Table 15; Figure 13). Most indicators suggest that sites downstream of the Mexican border (i.e., the Tijuana River mainstem and Tecate Creek) were more severely degraded than streams entirely within the United States. Sites in the northern interior parts of the watershed (such as Cottonwood, Pine Valley, and La Posta Creeks), were much less impacted.

Almost every indicator suggested that the mainstem site on the Tijuana

River (TJR05) was the most severely degraded site in the HU. Water quality was heavily impacted at TJR05. Many anthropogenic organic constituents were detected in water samples from this site, including nearly every PAH. Seven constituents exceeded aquatic life standards, and seven exceeded human health standards. Aquatic life exceedances were observed for several nutrients, selenium, copper, benzo(a)pyrene, pH, and specific conductivity. Human health exceedances were observed for a number of PAHs. However, the number of potentially problematic constituents may be underestimated because many of the constituents detected at this site had no applicable thresholds. Toxicity was severe, as all samples caused lethal or sub-lethal responses from multiple indicators. Bioassessment samples collected near TJR05 were in very poor ecological condition and had the lowest mean IBI score (i.e., 8.6) in the entire HU. Although multiple sources may account for the severe degradation observed at the lower mainstem of the Tijuana River, the high number of PAHs, as well as elevated specific conductivity, are consistent with pollution caused by industrial discharges and urban runoff (Institute for Regional Studies of the Californias 2005). However, other sources of impacts, such as physical habitat alteration, were not assessed.

Tecate Creek was also severely degraded. Like the mainstem of the

Tijuana River, Tecate Creek’s watershed is mostly within Mexico. Similarly, the same suite of water chemistry constituents exceeded aquatic life thresholds in Tecate Creek, and a high number of PAHs and pesticides were detected. However, no human health thresholds were exceeded. Nutrients, selenium, manganese, dissolved oxygen, conductivity, and turbidity accounted for the exceedances of aquatic life thresholds. Toxicity at Tecate Creek was severe, and all samples caused lethal or sub-lethal toxicity to multiple indicators. Unlike the Tijuana River mainstem, agricultural activities are common in the Tecate Creek watershed, and industrial activities are less intense. This difference in land use may account for the higher number of pesticides (5 vs. 3) and lower number of PAHs (26 vs. 45) detected in Tecate Creek water samples.

The remaining sites included in the study occurred on sites draining

watersheds exclusively within the United States, and impacts at these sites were less severe than Tijuana River or Tecate Creek. For example, the water samples

36


from site at the bottom of the Cottonwood Creek watershed (CWD10) exceeded fewer aquatic life thresholds, and no human health thresholds. Nutrients, selenium, manganese, and pH accounted for the exceedances of aquatic life thresholds. Toxicity was less severe than at Tecate Creek or the Tijuana River mainstem, as sediment samples did not increase mortality in H. azteca. Although no bioassessment samples were collected near the SWAMP site on Cottonwood Creek, samples collected several kilometers up in the watershed above Morena Lake were frequently in fair or good condition.

The site on La Posta Creek (LAP04), a tributary of Cottonwood Creek,

was in better ecological health than the other sites sampled under SWAMP. Only three water chemistry constituents (i.e., ammonia-N, total N, and dissolved oxygen) exceeded aquatic life thresholds, and these exceedances were observed on only one sampling date. Although all water and sediment samples were toxic to two indicator species (i.e., H. azteca and S. capricornutum), water samples did not affect a third species (C. dubia). However, bioassessment samples were frequently in poor condition (mean IBI 30.0), and an assessment of physical habitat suggested impacts to a few components of physical habitat (e.g., embeddedness and sediment deposition). Reconnaissance by San Diego Water Board staff observed intense grazing activity at this site (Lillian Busse, personal communication), which may account for the observed poor biological health and degradations to physical habitat (Braccia and Voshell 2007).

Other sites sampled under SWAMP were also located in the northern

interior of the HU. Although only one indicator of ecological health was assessed (i.e., biological integrity), samples collected from these sites (Los Coches Creek 2 and Pine Valley Creek 1) were both in fair or good condition. Most bioassessment samples collected at other sites in this portion of the HU were also in fair or better condition. The healthy biological communities observed at Pine Valley Creek are not consistent with the inclusion of this stream on the 303(d) list of impaired waterbodies. However, listed stressors at Pine Valley Creek (i.e., Enterococcus bacteria, phosphorus, and turbidity) were not assessed in this study.

This study’s assessment of the Tijuana HU suggests that portions of the

watershed are in poor ecological health, but the northern interior is in fair or good health. Multiple lines of evidence support this conclusion. For water chemistry, toxicity, and macroinvertebrate communities were in poor or very poor condition at the bottom of watersheds draining lands from Mexico, while all indicators were in better condition at sites in the northern interior of the HU.

Although these impacts affected all sites, this study showed that, at least

for water chemistry indicators, impacts were limited to certain constituents, such as nutrients and physical parameters. In contrast, metals (except manganese and copper) were below applicable thresholds at every site, as were nearly all

37


pesticides. Human health impacts were restricted to the mainstem site of the Tijuana River, and these impacts were observed on a single sampling date.

Despite the strength of the evidence, limitations of this study affect the

assessment. These limitations include difficulties integrating data from SWAMP and non-SWAMP sources, the non-randomization of sample sites, small sample size, unequal assessment effort at all sites, and the lack of applicable thresholds for several indicators. Although these limitations require that results be interpreted with caution, it is unlikely that they would alter the fundamental finding that the Tijuana HU is in poor condition near the Mexican border, and in better condition in the northern parts of the watershed, as explained at the end of this section.

The geographical approach to integrating SWAMP and non-SWAMP data

relies on assumptions about the spatial and temporal variability of the variables measured by these programs. For example, bioassessment data may have been collected up to 500 meters away and up to 6 years before water chemistry and toxicity data were collected. This study assumes that anthropogenic impacts do not change across these distances or over these spans of time. There is little published research on either of these assumptions, although there may be greater support for the assumptions about spatial variability (e.g., Gebler 2004) than for temporal variability (e.g., Sandin and Johnson 2000, Bêche et al. 2006). In this study, bioassessment data were observed to be highly variable, and the use of data collected many years before water chemistry data is questionable.

The targeted selection of sites monitored under the SWAMP program

facilitated integration of pre-existing data from non-SWAMP sources, but this non-probabilistic approach severely limits the extrapolation of data from these sites to the rest of the watershed. Non-random sampling violates assumptions underlying most statistical analyses, and the sites selected in this study cannot be assumed to represent the entire watershed (Olsen et al. 1999, Stevens Jr. and Olsen 2004).

The small number of sites monitored under SWAMP also limits the

certainty of this study’s assessment. Although SWAMP has produced a wealth of data about the Tijuana watershed using limited resources, some indicators (especially those with high variability) may require more extensive sampling to produce more precise and accurate assessments.

Although coverage was extensive in some regions, such as the upper

Cottonwood Creek watershed, sites were more sparse in other regions, such as Campo Creek, Pine Valley Creek, and the upper portions of the Río Seco (in the southeastern portion of the HU). The lack of data from Mexican portions of the watershed make it difficult to assess causes of impacts to sites receiving water across the national border, such as Tecate Creek and the lower mainstem of the Tijuana River.

38


Thresholds are an essential tool for assessing water quality and ecological

health. However, their use is limited to indicators that have been well studied, and they cannot provide a holistic view of watershed health. This limitation is exacerbated by the many constituents and indicators that lack applicable thresholds. For example, of the 155 water chemistry constituents, 93 (60%) had no applicable water quality objectives that could be used as thresholds for water quality. No thresholds exist for physical habitat scores. Furthermore, thresholds applied to IBI scores and toxicity were based on statistical distributions and professional judgment (respectively), rather than on risks to ecological health. For example, the 80% threshold used to identify toxic samples is based on the assumption that this level is ecologically meaningful, although this assumption has not been verified in the field. The development of biocriteria to establish meaningful thresholds for bioassessment is subject of active interest in California (Bernstein and Schiff 2002).

Despite these limitations, the data gathered under SWAMP and other

programs strongly support the conclusion that portions of the Tijuana HU are in poor ecological health, and others are in good health. Some of these limitations (such as the lack of applicable thresholds and the small sample size) may in fact have caused this assessment to underestimate the severity of degradation in the watershed. All indicators showed signs of human impacts. Multiple stressors, including degraded water quality, sediment, and physical habitat are the likely cause of the impact. Future research (see final report on the SWAMP monitoring program for further study recommendations) is necessary to determine which stressors are responsible for the impacts seen in the watershed. Table 15. Summary of the ecological health for five SWAMP sites in Tijuana HU. Toxicity frequency is frequency of toxicity for three chronic toxicity endpoints: C. dubia (fecundity), H. azteca (growth), and S. capricornutum (total cell count). Biology frequency is the frequency of IBIs below 40. nt = Indicator not tested.

Water chemistry Toxicity Biology* PhysicalAquatic life Human health habitat

Site # exceedances # exceedances Frequency Frequency Mean score911TCWD10 5 0 1.00 nt nt911TLAP04 3 0 0.80 0.60 13911TTET02 7 0 1.00 nt nt911TTJR05 7 7 1.00 1.00 nt911TJLCC2 nt nt nt -- nt911TJPVC1 nt nt nt -- nt * = Estimated from data collected at nearby (within 500 meters) non-SWAMP sites

39


Figure 13. Summary of the ecological health of SWAMP sites in the Tijuana HU, as determined by water chemistry, toxicity, and bioassessment indicators. Each pie slice corresponds to a specific indicator, as described in the inset, with darker colors corresponding to more degraded conditions (unmeasured indicators are shown in cross-hatched gray). The top-left slice corresponds to the number of water chemistry constituents exceeding aquatic life thresholds. The bottom slice corresponds to the frequency of toxicity among three endpoints: C. dubia (fecundity), H. azteca (growth), and S. capricornutum (total cell count). The top-right slice corresponds to the IBI of bioassessment samples.

40


6. LITERATURE CITED

Bêche, L.A., E.P. McElravy and V.H. Resh. 2005. Long-term seasonal variation in the biological traits of benthic-macroinvertebrates in two Mediterranean climate streams in California, USA. Freshwater Biology 51:56-75. Bernstien, B. and Schiff, K. 2002. Stormwater research needs in Southern California. Technical Report 358. Southern California Coastal Water Research Project. Westminster, CA. Braccia, A. and Voshell, JR. 2007. Benthic macroinvertebrate responses to increasing levels of cattle grazing in Blue Ridge Mountain streams, Virginia, USA. Environmental Monitoring and Assessment. 131: 185-200. California Code of Regulations. 2007. Barclay’s Official California Code of Regulations. Title 22. Social Security Division 4. Environmental Health Chapter 15. Domestic Water Quality and Monitoring Regulations Article 16. Secondary Drinking Water Standards. §64449. California Department of Fish and Game. 2003. California Stream Bioassessment Procedure: Protocol for Biological and Physical/Habitat Assessment in Wadeable Streams. Available from www.dfg.ca.gov/cabw/cabwhome.html. California Department of Water Resources. 2007. http://www.water.ca.gov/. Center for Earth Systems Analysis Research. 2000. Tijuana River Watershed Digital Land Use File. Available from http://geography.sdsu.edu/Resources/Data/Clearinghouse/trw.php. Environmental Protection Agency (EPA). 1993. Methods for measuring acute toxicity of effluents and receiving waters to freshwater and marine organisms, Fourth Edition. EPA 600/4-90/027. US Environmental Protection Agency, Environmental Research Laboratory. Duluth, MN. Environmental Protection Agency (EPA). 1997. Water quality standards: Establishment of numeric criteria for priority toxic pollutants for the state of California: Proposed Rule. Federal Register 62:42159-42208. Environmental Protection Agency (EPA). 2002. National recommended water quality criteria. EPA-822-R-02-047. Environmental Protection Agency Office of Water. Washington, DC.

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http://www.water.ca.gov/

http://geography.sdsu.edu/Resources/Data/Clearinghouse/trw.php


Environmental Protection Agency (EPA). 2007. Integrated Risk Information System. http://www.epa.gov/iris/index.html. Office of Research and Development. Washington, DC. Gebler, J.B. 2004. Mesoscale spatial variability of selected aquatic invertebrate community metrics from a minimally impaired stream segment. Journal of the North American Benthological Society 23:616-633. Institute for Regional Studies of the California. 2005. Tijuana River Watershed Atlas. San Diego University Press. San Diego, CA. National Academy of Sciences. 1977. Drinking Water and Health. Volume 1. Washington, DC. National Oceanic and Atmospheric Administration. 2007. National Weather Service data. Available from http://www.wrh.noaa.gov/sgx/obs/rtp/rtpmap.php?wfo=sgx Ode, P.R., A.C. Rehn and J.T. May. 2005. A quantitative tool for assessing the integrity of southern California coastal streams. Environmental Management 35:493-504. Olsen, A.R., J. Sedransk, D. Edwards, C.A. Gotway, W. Liggett, S. Rathburn, K.H. Reckhow and L.J. Young. 1999. Statistical issues for monitoring ecological and natural resources in the United States. Environmental Management and Assessment 54:1-45. Puckett, M. 2002. Quality Assurance Management Plan for the State of California's Surface Water Ambient Monitoring Program: Version 2. California Department of Fish and Game, Monterey, CA. Prepared for the State Water Resources Control Board. Sacramento, CA. California Regional Water Quality Control Board, San Diego Region. 1994. Water quality control plan for the San Diego Region. San Diego, CA. http://www.waterboards.ca.gov/sandiego/programs/basinplan.html SANDAG. 1998. Watersheds of the San Diego Region. SANDAG INFO. Sandin, L. and R.K. Johnson. 2000. The statistical power of selected indicator metrics using macroinvertebrates for assessing acidification and eutrophication of running waters. Hydrobiologia 422/423:233-243. Stevans, Jr., D.L. and A.R. Olsen. 2004. Spatially balanced sampling of natural resources. Journal of the American Statistical Association: Theory and Methods 99:262-278.

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http://www.epa.gov/iris/index.html

http://www.wrh.noaa.gov/sgx/obs/rtp/rtpmap.php?wfo=sgx


Weston Solutions, Inc. 2007. San Diego County Municipal Copermittees 2005-2006 Urban Runoff Monitoring. Final Report. County of San Diego. San Diego, CA. Available at http://www.projectcleanwater.org/html/wg_monitoring_05-06report.html.

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44

7. APPENDICES


APPENDIX I

A. Beneficial uses of streams in the Tijuana HU (California Regional Water Quality Control Board, San Diego Region 1994). B. Streams on the 303(d) list of impaired water bodies in the Tijuana HUC. HUC = Hydrologic Unit Code. MUN = Municipal and domestic supply. AGR = Agricultural supply. IND = Industrial service supply. IND = Industrial service supply. PROC = Industrial processing. FRSH = Freshwater supply. REC1 = Contact recreation. REC2 = Non-contact recreation. WARM = Warm freshwater habitat. COLD = Cold freshwater habitat. WILD = Wildlife habitat. RARE = Rare, threatened, or endangered species. SPWN = Spawning habitat. X = Exempted from municipal supply. E = Existing beneficial use. P = Potential beneficial use. A. Beneficial uses of streams in the Tijuana HU. Tijuana River HUC MUN AGR IND PROC FRSH REC1 REC2 BIOL WARM COLD WILD RARE SPWNTijuana River 911.11 X P E E E E Moody Canyon 911.11 X P E E E

Smugglers Gulch 911.11 X P E E EGoat Canyon 911.11 X E P P E E E

Spring Canyon 911.12 X E P P E E EDillon Canyon 911.12 X E P P E E E Finger Canyon 911.12 X E P P E E EWruck Canyon 911.12 X E P P E E E

Unnamed intermittent streams 911.12 X E P P E E EUnnamed intermittent streams 911.21 X E E E ETijuana River 911.21 X E E E E

Tecate Creek 911.23 X E E E ECottonwood Creek 911.60 E E E E E P E E E E E

Kitchen Creek 911.60 E E E E E P E E E E E Long Canyon 911.60 E E E E E P E E E E E

Troy Canyon 911.60 E E E E E P E E E E EFred Canyon 911.60 E E E E E P E E E EHorse Canyon 911.60 E E E E E P E E E E

La Posta Creek 911.70 E E E E E E E E E ESimmons Canyon 911.70 E E E E E E E E E E

La Posta Creek 911.60 E E E E E P E E E EMorena Creek 911.50 E E E E E E E E E E E

Long Valley 911.50 E E E E E E E E E EBear Valley 911.50 E E E E E E E E E

Cottonwood Creek 911.30 E E E E E E E E E E E EHauser Creek 911.30 E E E E E E E E E E ESalazar Creek 911.30 E E E E E E E E E EBoneyard Canyon 911.30 E E E E E E E E E ESkye Valley 911.30 E E E E E E E E E EPine Valley Creek 911.41 E E E E E E E E E E E

Indian Creek 911.41 E E E E E E E E E ELucas Creek 911.41 E E E E E E E E E E

Noble Canyon 911.41 E E E E E E E E E E ELos Rasalies Ravine 911.42 E E E E E E E E E E Paloma Ravine 911.42 E E E E E E E E E E

Bonita Ravine 911.42 E E E E E E E E E EChico Ravine 911.42 E E E E E E E E E E

Madero Ravine 911.42 E E E E E E E E E ELos Gatos Ravine 911.42 E E E E E E E E E EBoiling Spring Ravine 911.42 E E E E E E E E E E

Agua Dulce Creek 911.42 E E E E E E E E E EEscondido Ravine 911.42 E E E E E E E E E E

Scove Canyon 911.41 E E E E E E E E E EPine Valley Creek 911.30 E E E E E E E E E E E

Oak Valley 911.30 E E E E E E E E E E ENelson Canyon 911.30 E E E E E E E E E ESecret Canyon 911.30 E E E E E E E E E EHorsethief Canyon 911.30 E E E E E E E E E EEspinosa Creek 911.30 E E E E E E E E E E

I - 1


I - 2

Appendix I, continued. A. Beneficial uses in the Tijuana HU. Tijuana River HUC MUN AGR IND PROC FRSH REC1 REC2 BIOL WARM COLD WILD RARE SPWN

Wilson Creek 911.30 E E E E E E E E E EPats Canyon 911.30 E E E E E E E E E E E

Cottonwood Creek 911.23 X E E E EDry Valley 911.23 X E E E EBobOwens Canyon 911.23 X E E E EMcAlmond Canyon 911.24 X E E E EMcAlmond Canyon 911.23 X E E E ERattlesnake Canyon 911.23 X E E E EPotrero Creek 911.25 X E E E E

Little Potrero Creek 911.25 X E E E EPotrero Creek 911.23 X E E E E

Grapevine Creek 911.23 X E E E EBee Canyon 911.22 X E E E EBee Creek 911.23 X E E E E

Mine Canyon 911.21 X E E E EUnnamed intermittent streams 911.81 X E E E E B. 303(d)-listed streams in the Tijuana HU. Name HUC Stressor Source Area affectedPine Valley Creek (upper) 911.41 Enterococcus Grazing-related sources 2.9 miles

Concentrated animal feeding operationsTransient encampments

Phosphorus Source unknown 2.9 milesTurbidity Source unknown 2.9 miles

Tijuana River 911.11 Eutrophic Nonpoint/point source 6 milesIndicator bacteria Nonpoint/point source 6 milesLow dissolved oxygen Nonpoint/point source 6 milesPesticides Nonpoint/point source 6 milesSolids Nonpoint/point source 6 milesSynthetic organics Nonpoint/point source 6 milesTrace elements Nonpoint/point source 6 milesTrash Nonpoint/point source 6 miles


APPENDIX II Means, standard deviations (SD), and number of samples (n) of water chemistry constituents in (A) SWAMP sites and (B) Non-SWAMP (NPDES) sites. The watershed average was calculated as the mean of the site averages. Blank cells indicate that the constituent was not analyzed at that site. -- = Constituent not detected at that site. SWAMP sites were monitored in 2002. Non-SWAMP sites were monitored in Spring and Fall between 2002 and 2005. A. SWAMP sites.

II - 1


911TCWD10 911TLAP04 911TTET02 911TTJR05Type Constituent Unit Mean SD n Mean SD n Mean SD n Mean SD nInorganics Alkalinity as CaCO3 mg/L 203 6 2 295 24 4 605 20 4 397 64 2Inorganics Ammonia as mg/L 0.05 0.00 2 0.01 0.03 4 27.4 18.5 4 13.2 14.5 2Inorganics Nitrate as NO3 mg/L 0.40 0.57 2 0.34 0.39 4 0.01 0.01 4 0.01 0.01 2Inorganics Nitrite as N mg/L 0.010 0.014 2 0.002 0.004 4 0.153 0.151 4 0.006 0.003 2Inorganics Nitrogen, Total Kjeldahl mg/L 0.8 0.1 2 0.3 0.1 4 25.3 7.0 4 26.0 24.9 2Inorganics Phosphorus as P,Total mg/L 0.14 0.12 2 0.08 0.01 4 6.66 0.83 4 6.26 4.94 2Inorganics Selenium,Dissolved μg/L 6.9 0.9 2 2.2 1.5 4 10.5 3.9 4 11.0 1.6 2Inorganics Sulfate mg/L 113 41 2 64 11 4 329 19 4 309 106 2Metals Aluminum,Dissolved μg/L 0.3 0.5 2 2.5 3.1 4 9.8 3.9 4 9.4 4.2 2Metals Arsenic,Dissolved μg/L 1.0 0.3 2 1.7 0.5 4 5.6 0.9 4 6.8 1.8 2Metals Cadmium,Dissolved μg/L 0.03 0.01 2 0.07 0.02 4 0.07 0.05 4 0.06 0.04 2Metals Chromium,Dissolved μg/L 1.0 0.4 2 1.3 1.8 4 5.3 3.8 4 1.8 0.6 2Metals Copper,Dissolved μg/L 3.0 2.4 2 1.2 0.5 4 5.5 2.1 4 14.6 12.6 2Metals Lead,Dissolved μg/L 0.2 0.3 2 0.1 0.2 4 0.2 0.1 4 0.7 0.3 2Metals Manganese,Dissolved μg/L 51 50 2 30 11 4 499 80 4 318 157 2Metals Nickel,Dissolved μg/L 0.045 0.064 2 -- 0.000 4 23.075 5.305 4 8.765 1.110 2Metals Silver,Dissolved μg/L -- 0.00 2 -- 0.00 4 0.03 0.02 4 0.08 0.08 2Metals Zinc,Dissolved μg/L 1.0 0.2 2 0.5 0.1 4 5.7 1.8 4 13.9 14.2 2PAHs Acenaphthene μg/L -- 0 2 -- 0 4 -- 0 4 0.0065 0.0091 2PAHs Acenaphthylene μg/L -- 0 2 -- 0 4 -- 0 4 0.0078 0.0110 2PAHs Anthracene μg/L -- 0 2 -- 0 4 -- 0 4 0.0088 0.0002 2PAHs Benz(a)anthracene μg/L -- 0 2 -- 0 4 -- 0 4 0.0204 0.0288 2PAHs Benzo(a)pyrene μg/L -- 0 2 -- 0 4 -- 0 4 0.0399 0.0564 2PAHs Benzo(b)fluoranthene μg/L -- 0 2 -- 0 4 -- 0 4 0.0525 0.0742 2PAHs Benzo(e)pyrene μg/L -- 0 2 -- 0 4 -- 0 4 0.0730 0.1032 2PAHs Benzo(g,h,i)perylene μg/L -- 0 2 -- 0 4 -- 0 4 0.0825 0.1167 2PAHs Benzo(k)fluoranthene μg/L -- 0 2 -- 0 4 -- 0 4 0.0167 0.0235 2PAHs Biphenyl μg/L -- 0 2 -- 0 4 0.0074 0.0058 4 0.0286 0.0404 2PAHs Chrysene μg/L -- 0 2 -- 0 4 -- 0 4 0.0580 0.0820 2PAHs Chrysenes, C1 - μg/L -- 0 2 -- 0 4 -- 0 4 0.1135 0.1605 2PAHs Chrysenes, C2 - μg/L -- 0 2 -- 0 4 0.0048 0.0095 4 0.1365 0.1930 2PAHs Chrysenes, C3 - μg/L -- 0 2 -- 0 4 -- 0 4 0.1400 0.1980 2PAHs Dibenz(a,h)anthracene μg/L -- 0 2 -- 0 4 -- 0 4 0.0102 0.0144 2PAHs Dibenzothiophene μg/L -- 0 2 -- 0 4 0.0020 0.0040 4 0.0169 0.0238 2PAHs Dibenzothiophenes, C1 - μg/L -- 0 2 -- 0 4 0.0280 0.0106 4 0.1547 0.1970 2PAHs Dibenzothiophenes, C2 - μg/L -- 0 2 -- 0 4 0.0462 0.0173 4 0.4808 0.6679 2PAHs Dibenzothiophenes, C3 - μg/L -- 0 2 -- 0 4 0.0354 0.0173 4 0.4630 0.6548 2PAHs Dichlofenthion μg/L -- 0 2 -- 0 4 -- 0 4 -- 0.0000 2PAHs Dimethylnaphthalene, 2,6- μg/L -- 0 2 -- 0 4 0.0110 0.0150 4 0.1622 0.1681 2PAHs Dimethylphenanthrene, 3,6- μg/L -- 0 2 -- 0 4 0.0043 0.0086 4 0.0755 0.1068 2PAHs Fluoranthene μg/L -- 0 2 -- 0 4 0.0180 0.0048 4 0.1260 0.1782 2PAHs Fluoranthene/Pyrenes, C1 - μg/L -- 0 2 -- 0 4 0.0207 0.0178 4 0.3110 0.4398 2PAHs Fluorene μg/L -- 0 2 -- 0 4 0.0029 0.0058 4 0.0386 0.0546 2PAHs Fluorenes, C1 - μg/L -- 0 2 -- 0 4 0.0249 0.0189 4 0.2125 0.3005 2PAHs Fluorenes, C2 - μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PAHs Fluorenes, C3 - μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PAHs Indeno(1,2,3-c,d)pyrene μg/L -- 0 2 -- 0 4 -- 0 4 0.0272 0.0385 2PAHs Methyldibenzothiophene, 4- μg/L -- 0 2 -- 0 4 0.0097 0.0041 4 0.0560 0.0792 2PAHs Methylfluoranthene, 2- μg/L -- 0 2 -- 0 4 -- 0 4 0.0354 0.0500 2PAHs Methylfluorene, 1- μg/L -- 0 2 -- 0 4 0.0110 0.0070 4 0.0775 0.1096 2PAHs Methylnaphthalene, 1- μg/L -- 0 2 -- 0 4 -- 0 4 0.0589 0.0736 2PAHs Methylnaphthalene, 2- μg/L -- 0 2 -- 0 4 -- 0 4 0.0885 0.1252 2PAHs Methylphenanthrene, 1- μg/L -- 0 2 -- 0 4 0.0087 0.0037 4 0.0505 0.0714 2PAHs Naphthalene μg/L -- 0 2 -- 0 4 -- 0 4 0.0590 0.0834 2PAHs Naphthalenes, C1 - μg/L -- 0 2 -- 0 4 0.0025 0.0051 4 0.1542 0.1978 2PAHs Naphthalenes, C2 - μg/L -- 0 2 -- 0 4 0.0211 0.0212 4 0.4582 0.5428 2PAHs Naphthalenes, C3 - μg/L -- 0 2 -- 0 4 0.0840 0.0867 4 0.7626 1.0428 2PAHs Naphthalenes, C4 - μg/L -- 0 2 -- 0 4 0.0325 0.0497 4 0.2274 0.2709 2

II - 2


Appendix IIa, continued. Means and standard deviations of water chemistry constituents.

II - 3


911TCWD10 911TLAP04 911TTET02 911TTJR05Type Constituent Unit Mean SD n Mean SD n Mean SD n Mean SD nPAHs Perylene μg/L -- 0 2 -- 0 4 -- 0 4 0.0155 0.0219 2PAHs Phenanthrene μg/L -- 0 2 -- 0 4 0.0272 0.0114 4 0.1005 0.1421 2PAHs Phenanthrene/Anthracene, C1 - μg/L -- 0 2 -- 0 4 0.0694 0.0359 4 0.2765 0.3910 2PAHs Phenanthrene/Anthracene, C2 - μg/L -- 0 2 -- 0 4 0.0866 0.0601 4 0.7700 1.0889 2PAHs Phenanthrene/Anthracene, C3 - μg/L -- 0 2 -- 0 4 0.0250 0.0180 4 0.6050 0.8556 2PAHs Phenanthrene/Anthracene, C4 - μg/L -- 0 2 -- 0 4 0.0044 0.0088 4 0.1580 0.2234 2PAHs Pyrene μg/L -- 0 2 -- 0 4 0.0162 0.0067 4 0.1250 0.1768 2PAHs Trimethylnaphthalene, 2,3,5- μg/L -- 0 2 -- 0 4 0.0233 0.0163 4 0.0700 0.0990 2PCBs PCB 005 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 008 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 015 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 018 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 027 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 028 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 029 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 031 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 033 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 044 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 049 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 052 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 056 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 060 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 066 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 070 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 074 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 087 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 095 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 097 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 099 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 101 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 105 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 110 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 114 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 118 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 128 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 137 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 138 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 141 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 149 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 151 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 153 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 156 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 157 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 158 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 170 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 174 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 177 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 180 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 183 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 187 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 189 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 194 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 195 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 200 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 201 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 203 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 206 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2PCBs PCB 209 μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Aldrin μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Aspon μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Azinphos ethyl μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Azinphos methyl μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Bolstar μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Carbophenothion μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Chlordane, cis- μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Chlordane, trans- μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Chlordene, alpha- μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Chlordene, gamma- μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2

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Appendix IIa, continued. Means and standard deviations of water chemistry constituents. 911TCWD10 911TLAP04 911TTET02 911TTJR05

Type Constituent Unit Mean SD n Mean SD n Mean SD n Mean SD nPesticides Chlorfenvinphos μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Chlorpyrifos μg/L -- 0 2 -- 0 4 -- 0.006 4 -- 0 2Pesticides Chlorpyrifos methyl μg/L -- 0 2 -- 0 4 -- 0.012 4 -- 0 2Pesticides Ciodrin μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Coumaphos μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Dacthal μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides DDD(o,p') μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides DDD(p,p') μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides DDE(o,p') μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides DDE(p,p') μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides DDMU(p,p') μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides DDT(o,p') μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides DDT(p,p') μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Demeton-s μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Diazinon μg/L 0.0050 0.0071 2 0.0078 0.0100 4 0.0245 0.0193 4 0.0320 0.0453 2Pesticides Dichlorvos μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Dicrotophos μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Dieldrin μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Dimethoate μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Dioxathion μg/L -- 0 2 -- 0 4 0.2290 0.3787 4 0.1220 0.1725 2Pesticides Disulfoton μg/L -- 0 2 -- 0 4 0.0153 0.0305 4 0.0665 0.0940 2Pesticides Endosulfan I μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Endosulfan II μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Endosulfan sulfate μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Endrin Aldehyde μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Endrin Ketone μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Endrin μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Ethion μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Ethoprop μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Famphur μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Fenchlorphos μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Fenitrothion μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Fensulfothion μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Fenthion μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Fonofos μg/L -- 0 2 -- 0 4 0.0135 0.0270 4 -- 0 2Pesticides HCH, alpha μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides HCH, beta μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides HCH, delta μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides HCH, gamma μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Heptachlor epoxide μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Heptachlor μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Hexachlorobenzene μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Leptophos μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Malathion μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Merphos μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Methidathion μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Methoxychlor μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Mevinphos μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Mirex μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Molinate μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Naled μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Nonachlor, cis- μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Nonachlor, trans- μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Oxadiazon μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Oxychlordane μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Parathion, Ethyl μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Parathion, Methyl μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Phorate μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Phosmet μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Phosphamidon μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Sulfotep μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Tedion μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Terbufos μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Tetrachlorvinphos μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Thiobencarb μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Thionazin μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Tokuthion μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Pesticides Trichlorfon μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2

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II - 6

Appendix IIa, continued. Means and standard deviations of water chemistry constituents. 911TCWD10 911TLAP04 911TTET02 911TTJR05

Type Constituent Unit Mean SD n Mean SD n Mean SD n Mean SD nPesticides Trichloronate μg/L -- 0 2 -- 0 4 -- 0 4 -- 0 2Physical Oxygen, Dissolved mg/L 11.2 8.7 2 8.0 2.3 4 5.0 2.2 4 12.5 1.7 2Physical Oxygen, Saturation % 125 98 2 74 16 4 58 22 4 150 48 2Physical pH pH units 7.9 0.7 2 7.4 0.5 4 7.7 0.3 4 9.1 0.5 2Physical Salinity ppt 0.7 0.1 2 0.4 0.0 4 1.3 0.1 4 0.5 0.7 2Physical Specific conductivity μS/cm 1307 187 2 782 58 4 2465 178 4 1090 1520 2Physical Suspended Solids,Total mg/L 5.4 7.7 2 0.4 0.8 4 52.1 22.8 4 105.6 96.3 2Physical Temperature ºC 20.5 0.7 2 12.4 4.1 4 23.5 5.1 4 23.8 9.9 2Physical Turbidity NTU 3.1 2.6 2 0.6 0.6 4 19.1 9.8 4 31.4 4.7 2Physical Velocity ft/sec 0 1.5 1.8 2 2.4 0 3 0 B. Non-SWAMP sites.

Dissolved Specific Turbidity Temperatureoxygen (mg/L) pH conductivity (mS/cm) (NTU) (ºC)

Station Mean SD n Mean SD n Mean SD n Mean SD n Mean SD nSite 2 (CC-H94) 1.5 1 7.3 1 2.28 1 7.6 1 17.4 1Site 11 (REF-WC) 19.1 1 8.1 1 0.36 1 0 17.9 1Site 12 (CC-C) 9.1 7.7 3 7.4 0.2 3 1.02 0.15 3 0 14.6 1.8 3Site 14 (TJ-DM) 6.5 3.0 2 7.5 0.7 2 2.39 1.14 2 56.2 1 18.7 1.2 2


APPENDIX III Results from toxicity assays for each endpoint at each site in the watershed. Mean = mean percent control. SD = standard deviation.

C. dubia H. azteca S. capricornutumSampling Survival Young / Female Survival Growth Total cell count

Site events n Mean SD n Mean SD n Mean SD n Mean SD n Mean SD911TCWD10 1 0 0 1 122 1 95 0911TLAP04 4 1 105 1 103 3 104 12 3 139 19 1 120911TTET02 2 0 0 2 17 21 1 108 1 9911TTJR05 2 0 0 2 15 13 2 102 12 0All sites in watershed 9 1 105 1 103 8 62 51 7 118 24 2 64 79

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APPENDIX IV Mean IBI and metric scores for bioassessment sites in the Tijuana HU. Note that the number listed under IBI is the mean IBI for each site, and not the IBI calculated from the mean metric values.

EPT Coleoptera Predator % Non-insect % TolerantIBI Taxa Taxa Taxa % Collectors % Intolerant Taxa Taxa

Site Season n Years Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD911TLAP04 Average 5 2000-2005 30.0 4.0 4.4 0.1 2.2 1.2 3.5 0.7 2.3 1.8 1.3 0.4 3.8 0.4 3.7 0.5

Fall 2 2000-2005 32.9 10.1 4.5 0.7 3.0 1.4 3.0 0.0 3.5 2.1 1.5 0.7 3.5 0.7 4.0 1.4Spring 3 2001-2005 27.1 15.1 4.3 1.5 1.3 2.3 4.0 3.6 1.0 1.0 1.0 0.0 4.0 1.0 3.3 2.3

911TTJR05 Spring 1 2003 8.6 0.0 0.0 0.0 2.0 0.0 2.0 2.0911TJLCC2 Spring 2 2001-2006 58.6 20.2 6.5 3.5 3.0 1.4 5.5 4.9 5.0 4.2 5.5 2.1 7.5 0.7 8.0 1.4911TJPVC1 Spring 1 2006 70.0 7.0 5.0 2.0 10.0 10.0 8.0 7.0Site 1 Average 6 2000-2005 53.3 2.6 3.9 1.3 5.3 0.4 6.3 1.0 9.2 1.1 3.9 1.3 4.4 0.6 4.3 0.4

Fall 1 2000 51.4 3.0 5.0 7.0 10.0 3.0 4.0 4.0Spring 5 2000-2005 55.1 8.5 4.8 0.8 5.6 3.8 5.6 3.2 8.4 2.2 4.8 4.8 4.8 0.8 4.6 1.5

Site 2 Average 3 2000-2003 37.1 14.1 4.3 1.1 2.5 2.1 4.0 1.4 4.5 2.1 2.5 2.1 4.3 1.1 4.0 0.0Fall 1 2000 47.1 5.0 4.0 5.0 6.0 4.0 5.0 4.0Spring 2 2001-2003 27.1 14.1 3.5 0.7 1.0 1.4 3.0 1.4 3.0 1.4 1.0 0.0 3.5 3.5 4.0 2.8

Site 3 Spring 1 2001 60.0 3.0 8.0 7.0 8.0 4.0 8.0 4.0Site 4 Spring 1 2001 60.0 3.0 8.0 8.0 4.0 5.0 8.0 6.0Site 7 Average 2 1999-2001 35.0 23.2 4.0 1.4 2.0 0.0 2.5 0.7 5.5 6.4 3.5 3.5 3.5 2.1 3.5 3.5

Fall 1 1999 51.4 5.0 2.0 2.0 10.0 6.0 5.0 6.0Spring 1 2001 18.6 3.0 2.0 3.0 1.0 1.0 2.0 1.0

Site 8 Spring 6 2001-2005 38.3 13.3 2.8 1.6 4.3 2.9 3.7 2.4 4.7 3.5 2.0 3.0 5.2 1.3 4.2 1.6Site 9 Average 5 1999-2005 55.2 5.4 6.8 0.4 4.8 0.2 4.3 0.4 6.3 0.5 5.5 2.1 5.3 1.1 5.8 0.4

Fall 3 1999-2005 59.0 12.1 7.0 2.0 4.7 0.6 4.0 3.5 6.7 3.5 7.0 4.4 6.0 1.7 6.0 1.7Spring 2 2000-2001 51.4 16.2 6.5 0.7 5.0 0.0 4.5 2.1 6.0 5.7 4.0 2.8 4.5 0.7 5.5 0.7

Site 10 Average 5 2000-2005 47.3 16.4 4.0 1.4 5.9 1.2 6.0 2.8 4.4 1.9 2.8 2.5 5.1 1.6 5.0 0.0Fall 1 2000 35.7 3.0 5.0 4.0 3.0 1.0 4.0 5.0Spring 4 2000-2005 58.9 8.6 5.0 2.9 6.8 2.4 8.0 2.7 5.8 3.1 4.5 4.0 6.3 1.9 5.0 1.4

Site 11 Spring 1 2001 32.9 7.0 0.0 3.0 3.0 2.0 4.0 4.0Site 12 Average 3 2004-2005 11.1 3.5 1.0 1.4 0.5 0.7 2.5 0.7 2.8 0.4 0.0 0.0 0.5 0.7 0.5 0.7

Fall 1 2004 8.6 0.0 0.0 3.0 3.0 0.0 0.0 0.0Spring 2 2004-2005 13.6 11.1 2.0 1.4 1.0 1.4 2.0 2.8 2.5 2.1 0.0 0.0 1.0 1.4 1.0 1.4

Site 13 Spring 1 2005 51.4 3.0 5.0 5.0 2.0 2.0 10.0 9.0

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surface water ambient monitoring program (swamp) · swamp report on the tijuana hydrologic unit...

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